diff --git a/app/controllers/networks_controller.rb b/app/controllers/networks_controller.rb
index 2f8cedaa..656db6c8 100644
--- a/app/controllers/networks_controller.rb
+++ b/app/controllers/networks_controller.rb
@@ -78,7 +78,7 @@ def tag
     @topics     = tags_array
     @topic      = tags_array.join(' + ')
     @topic_user = nil
-    @networks   = tags_array.map { |tag| Network.networks_for_tag(tag) }.flatten.uniq if @networks.nil?
+    @networks   = tags_array.flat_map { |tag| Network.networks_for_tag(tag) }.uniq if @networks.nil?
   end
 
   def mayor
diff --git a/app/controllers/opportunities_controller.rb b/app/controllers/opportunities_controller.rb
index d93b83c9..f76fc7ca 100644
--- a/app/controllers/opportunities_controller.rb
+++ b/app/controllers/opportunities_controller.rb
@@ -88,7 +88,7 @@ def index
 
     chosen_location = 'Worldwide' if chosen_location.nil?
     @locations = Rails.cache.fetch("job_locations_#{params[:location]}_#{params[:skill]}", expires_in: 1.hour) do
-      Opportunity.by_tag(tag).map(&:locations).flatten.reject { |loc| loc == "Worldwide" }.push("Worldwide").uniq.compact
+      Opportunity.by_tag(tag).flat_map(&:locations).reject { |loc| loc == "Worldwide" }.push("Worldwide").uniq.compact
     end
     @locations.delete(chosen_location) unless @locations.frozen?
     params[:location] = chosen_location
@@ -147,11 +147,11 @@ def stringify_location
   end
 
   def all_job_locations
-    Rails.cache.fetch('job_locations', expires_in: 23.hours) { Opportunity.all.map(&:locations).flatten.push("Worldwide").uniq.compact }
+    Rails.cache.fetch('job_locations', expires_in: 23.hours) { Opportunity.all.flat_map(&:locations).push("Worldwide").uniq.compact }
   end
 
   def all_job_skills
-    Rails.cache.fetch('job_skills', expires_in: 23.hours) { Opportunity.all.map(&:tags).flatten.uniq.compact }
+    Rails.cache.fetch('job_skills', expires_in: 23.hours) { Opportunity.all.flat_map(&:tags).uniq.compact }
   end
 
   def closest_to_user(user)
diff --git a/app/controllers/protips_controller.rb b/app/controllers/protips_controller.rb
index c10a9af0..fe8eabd6 100644
--- a/app/controllers/protips_controller.rb
+++ b/app/controllers/protips_controller.rb
@@ -525,7 +525,7 @@ def suggested_networks
       @protips.facets['suggested-networks']['terms'].map { |h| h['term'] }
     else
       #gets top 10 tags for the protips and picks up associated networks
-      Network.tagged_with(@protips.map(&:tags).flatten.reduce(Hash.new(0)) { |h, t| h[t] += 1; h }.sort_by { |k, v| -v }.first(10).flatten.values_at(*(0..20).step(2))).select(:slug).limit(4).map(&:slug)
+      Network.tagged_with(@protips.flat_map(&:tags).reduce(Hash.new(0)) { |h, t| h[t] += 1; h }.sort_by { |k, v| -v }.first(10).flatten.values_at(*(0..20).step(2))).limit(4).pluck(:slug)
     end
   end
 
@@ -545,7 +545,7 @@ def get_topics_from_protips(protips)
       topics = protips.facets['top-tags']['terms'].map { |h| h['term'] }
     end
 
-    topics = protips.map(&:tags).flatten.uniq.first(8) if topics.blank? && protips.present?
+    topics = protips.flat_map(&:tags).uniq.first(8) if topics.blank? && protips.present?
     topics
   end
 
diff --git a/app/controllers/teams_controller.rb b/app/controllers/teams_controller.rb
index d1b14ee8..1b327057 100644
--- a/app/controllers/teams_controller.rb
+++ b/app/controllers/teams_controller.rb
@@ -290,7 +290,7 @@ def team_from_params(opts)
   end
 
   def replace_section(section_name)
-    section_name = section_name.gsub('-', '_')
+    section_name = section_name.tr('-', '_')
     "$('##{section_name}').replaceWith('#{escape_javascript(render(:partial => section_name))}');"
   end
 
@@ -313,7 +313,7 @@ def page_based_on_rank(rank)
 
   def job_public_ids
     Opportunity
-    Rails.cache.fetch('all-jobs-public-ids', :expires_in => 1.hour) { Opportunity.select(:public_id).group('team_id, created_at, public_id').map(&:public_id) }
+    Rails.cache.fetch('all-jobs-public-ids', :expires_in => 1.hour) { Opportunity.group('team_id, created_at, public_id').pluck(:public_id) }
   end
 
   def next_job(job)
diff --git a/app/helpers/badges_helper.rb b/app/helpers/badges_helper.rb
index afb15099..7612404e 100644
--- a/app/helpers/badges_helper.rb
+++ b/app/helpers/badges_helper.rb
@@ -8,7 +8,7 @@ def share_coderwall_on_twitter
   end
 
   def dom_tag(tag)
-    sanitize_dom_id(tag).gsub(' ', '-').gsub('+', 'plus').gsub('#', 'sharp')
+    sanitize_dom_id(tag).tr(' ', '-').gsub('+', 'plus').gsub('#', 'sharp')
   end
 
   def dom_for_badge(badge)
@@ -27,4 +27,4 @@ def unlocked_badge_title
     "#{@user.short_name} leveled up and unlocked the #{@badge.display_name} on Coderwall"
   end
 
-end
\ No newline at end of file
+end
diff --git a/app/helpers/premium_helper.rb b/app/helpers/premium_helper.rb
index 428f58e8..fabf55c6 100644
--- a/app/helpers/premium_helper.rb
+++ b/app/helpers/premium_helper.rb
@@ -70,7 +70,7 @@ def panel_form_for_section(section_id, title = nil, show_save_button = true, &bl
   end
 
   def partialify_html_section_id(section_id)
-    section_id.to_s.gsub("-", "_").gsub('#', '')
+    section_id.to_s.tr("-", "_").gsub('#', '')
   end
 
   def add_active_class_to_first_member
diff --git a/app/helpers/protips_helper.rb b/app/helpers/protips_helper.rb
index 556e9ce2..c5fda5a5 100644
--- a/app/helpers/protips_helper.rb
+++ b/app/helpers/protips_helper.rb
@@ -285,7 +285,7 @@ def display_scope_class
   end
 
   def current_user_upvotes
-    @upvoted_protip_ids ||= current_user.upvoted_protips.select(:public_id).map(&:public_id)
+    @upvoted_protip_ids ||= current_user.upvoted_protips.pluck(:public_id)
   end
 
   def user_upvoted?(protip)
diff --git a/app/jobs/create_network_job.rb b/app/jobs/create_network_job.rb
index 945fafe8..d85b5f26 100644
--- a/app/jobs/create_network_job.rb
+++ b/app/jobs/create_network_job.rb
@@ -5,7 +5,7 @@ class CreateNetworkJob
 
   def perform(tag)
     top_tags = Protip.trending_topics
-    sub_tags = Protip.tagged_with([tag], on: :topics).collect(&:topics).flatten
+    sub_tags = Protip.tagged_with([tag], on: :topics).flat_map(&:topics)
     sub_tags.delete_if { |sub_tag| top_tags.include? sub_tag }
     unless sub_tags.blank?
       sub_tag_frequency = sub_tags.inject(Hash.new(0)) { |h, sub_tag| h[sub_tag] += 1; h }
diff --git a/app/models/badges/node_knockout.rb b/app/models/badges/node_knockout.rb
index e45f4d4b..e08fce8d 100644
--- a/app/models/badges/node_knockout.rb
+++ b/app/models/badges/node_knockout.rb
@@ -115,7 +115,7 @@ def github_for(path)
     begin
       res      = Servant.get("http://nodeknockout.com#{path}")
       doc      = Nokogiri::HTML(res.to_s)
-      username = doc.css("a.github").first[:href].gsub(/https?:\/\/github.com\//, '')
+      username = doc.css("a.github").first[:href].sub(/https?:\/\/github.com\//, '')
       role     = doc.css(".role").first.text
       Rails.logger.info "Found node knockout #{role}: #{username}" if ENV['DEBUG']
       return [role, username]
@@ -129,7 +129,7 @@ def twitter_for(path)
     begin
       res      = Servant.get("http://nodeknockout.com#{path}")
       doc      = Nokogiri::HTML(res.to_s)
-      username = doc.css("a.twitter").first[:href].gsub("http://twitter.com/", '').strip
+      username = doc.css("a.twitter").first[:href].sub("http://twitter.com/", '').strip
       role     = doc.css(".role").first.text
       Rails.logger.info "Found node knockout #{role}: #{username}"
       return [role, username]
diff --git a/app/models/badges/polygamous.rb b/app/models/badges/polygamous.rb
index f8b0e2a7..170f4c83 100644
--- a/app/models/badges/polygamous.rb
+++ b/app/models/badges/polygamous.rb
@@ -9,9 +9,9 @@ class Polygamous < BadgeBase
   def reasons
     @reasons ||= begin
       facts = user.facts.select { |fact| fact.tagged?('personal', 'repo', 'original') }
-      facts.collect do |fact|
+      facts.flat_map do |fact|
         fact.metadata[:languages]
-      end.flatten.uniq
+      end.uniq
     end
   end
 
@@ -19,4 +19,4 @@ def award?
     reasons.size >= 4
   end
 
-end
\ No newline at end of file
+end
diff --git a/app/models/blog_post.rb b/app/models/blog_post.rb
index 98fd8349..74b642b6 100644
--- a/app/models/blog_post.rb
+++ b/app/models/blog_post.rb
@@ -45,7 +45,7 @@ def all_entries
     end
 
     def id_of(pathname)
-      pathname.basename.to_s.gsub(pathname.extname, "")
+      pathname.basename.to_s.sub(pathname.extname, "")
     end
   end
 
@@ -83,4 +83,4 @@ def cached_content
     @cached_content ||= @content.read.split("---")
   end
 
-end
\ No newline at end of file
+end
diff --git a/app/models/concerns/team_analytics.rb b/app/models/concerns/team_analytics.rb
index af28b615..0a0ad3b0 100644
--- a/app/models/concerns/team_analytics.rb
+++ b/app/models/concerns/team_analytics.rb
@@ -67,7 +67,7 @@ def number_of_completed_sections(*excluded_sections)
       completed_sections = 0
 
       sections = (SECTIONS - excluded_sections).map do |section|
-        "has_#{section.gsub(/-/, '_')}?"
+        "has_#{section.tr('-', '_')}?"
       end
       sections.each do |section_complete|
         completed_sections += 1 if self.respond_to?(section_complete) &&
diff --git a/app/models/concerns/user_oauth.rb b/app/models/concerns/user_oauth.rb
index 6e1ecac9..bae380ea 100644
--- a/app/models/concerns/user_oauth.rb
+++ b/app/models/concerns/user_oauth.rb
@@ -94,8 +94,8 @@ def avatar_url_for(oauth)
     end
 
     def all_tokens
-      with_tokens.select("github_token").collect(&:github_token)
+      with_tokens.pluck(:github_token)
     end
 
   end
-end
\ No newline at end of file
+end
diff --git a/app/models/github_old.rb b/app/models/github_old.rb
index 5ce65fb6..aafdbdf4 100644
--- a/app/models/github_old.rb
+++ b/app/models/github_old.rb
@@ -113,7 +113,7 @@ def repos_for(github_username, since=Time.at(0))
   end
 
   def predominant_repo_lanugage_for_link(link)
-    owner, repo_name = *link.gsub(/https?:\/\/github.com\//i, '').split('/')
+    owner, repo_name = *link.sub(/https?:\/\/github.com\//i, '').split('/')
     repo(owner, repo_name)[:language]
   end
 
@@ -181,4 +181,4 @@ def repo_forks(owner, name, since=Time.at(0))
   rescue Errno::ECONNREFUSED => e
     retry
   end
-end
\ No newline at end of file
+end
diff --git a/app/models/lanyrd.rb b/app/models/lanyrd.rb
index d94787bd..eb5332d0 100644
--- a/app/models/lanyrd.rb
+++ b/app/models/lanyrd.rb
@@ -5,7 +5,7 @@ class Lanyrd < Struct.new(:username)
 
   def facts
     events.collect do |event|
-      id = event[:url].gsub(HOST, '') + ":#{username}"
+      id = event[:url].sub(HOST, '') + ":#{username}"
       Fact.append!(id, "lanyrd:#{username}", event[:name], event[:date], event[:url], event[:tags])
     end
   end
@@ -38,4 +38,4 @@ def profile
       {}
     end
   end
-end
\ No newline at end of file
+end
diff --git a/app/models/network.rb b/app/models/network.rb
index 5bf3d92f..f2525ab4 100644
--- a/app/models/network.rb
+++ b/app/models/network.rb
@@ -40,12 +40,12 @@ def slugify(name)
       if !!(name =~ /\p{Latin}/)
         name.to_s.downcase.gsub(/[^a-z0-9]+/i, '-').chomp('-')
       else
-        name.to_s.gsub(/\s/, "-")
+        name.to_s.tr(' ', '-')
       end
     end
 
     def unslugify(slug)
-      slug.gsub(/\-/, ' ')
+      slug.tr('-', ' ')
     end
 
     def all_with_tag(tag_name)
@@ -201,12 +201,12 @@ def expert_protips(limit=nil, offset =0)
   end
 
   def members(limit = -1, offset = 0)
-    members_scope = User.where(id: Follow.for_followable(self).select(:follower_id)).offset(offset)
+    members_scope = User.where(id: Follow.for_followable(self).pluck(:follower_id)).offset(offset)
     limit > 0 ? members_scope.limit(limit) : members_scope
   end
 
   def new_members(limit = nil, offset = 0)
-    User.where(id: Follow.for_followable(self).select(:follower_id).where('follows.created_at > ?', 1.week.ago)).limit(limit).offset(offset)
+    User.where(id: Follow.for_followable(self).where('follows.created_at > ?', 1.week.ago).pluck(:follower_id)).limit(limit).offset(offset)
   end
 
   def ranked_members(limit = 15)
diff --git a/app/models/protip.rb b/app/models/protip.rb
index cd4cfe64..83fa7986 100644
--- a/app/models/protip.rb
+++ b/app/models/protip.rb
@@ -121,7 +121,7 @@ def trending_topics
 
       unless trending_protips.respond_to?(:errored?) and trending_protips.errored?
         static_trending = ENV['FEATURED_TOPICS'].split(",").map(&:strip).map(&:downcase) unless ENV['FEATURED_TOPICS'].blank?
-        dynamic_trending = trending_protips.map { |p| p.tags }.flatten.reduce(Hash.new(0)) { |h, tag| h.tap { |h| h[tag] += 1 } }.sort { |a1, a2| a2[1] <=> a1[1] }.map { |entry| entry[0] }.reject { |tag| User.where(username: tag).any? }
+        dynamic_trending = trending_protips.flat_map { |p| p.tags }.reduce(Hash.new(0)) { |h, tag| h.tap { |h| h[tag] += 1 } }.sort { |a1, a2| a2[1] <=> a1[1] }.map { |entry| entry[0] }.reject { |tag| User.where(username: tag).any? }
         ((static_trending || []) + dynamic_trending).uniq
       else
         Tag.last(20).map(&:name).reject { |name| User.exists?(username: name) }
@@ -234,7 +234,7 @@ def search_trending_by_team(team_id, query_string, page, per_page)
       Protip.search(query, [], page: page, per_page: per_page)
     rescue Errno::ECONNREFUSED
       team = Team.where(slug: team_id).first
-      team.members.collect(&:protips).flatten
+      team.members.flat_map(&:protips)
     end
 
     def search_trending_by_user(username, query_string, tags, page, per_page)
@@ -259,7 +259,7 @@ def search_bookmarked_protips(username, page, per_page)
     end
 
     def most_interesting_for(user, since=Time.at(0), page = 1, per_page = 10)
-      search_top_trending_since("only_link:false", since, user.networks.map(&:ordered_tags).flatten.concat(user.skills.map(&:name)), page, per_page)
+      search_top_trending_since("only_link:false", since, user.networks.flat_map(&:ordered_tags).concat(user.skills.map(&:name)), page, per_page)
     end
 
     def search_top_trending_since(query, since, tags, page = 1, per_page = 10)
diff --git a/app/models/team.rb b/app/models/team.rb
index f687b41f..2a69597c 100644
--- a/app/models/team.rb
+++ b/app/models/team.rb
@@ -112,7 +112,7 @@ def self.slugify(name)
     if !!(name =~ /\p{Latin}/)
       name.to_s.downcase.gsub(/[^a-z0-9]+/i, '-').chomp('-')
     else
-      name.to_s.gsub(/\s/, "-")
+      name.to_s.tr(' ', '-')
     end
   end
 
diff --git a/app/models/teams/account.rb b/app/models/teams/account.rb
index 6f896312..a22debaf 100644
--- a/app/models/teams/account.rb
+++ b/app/models/teams/account.rb
@@ -118,7 +118,7 @@ def suspend!
     team.monthly_subscription = false
     team.valid_jobs           = false
     team.save
-    team.jobs.map { |job| job.deactivate! }
+    team.jobs.map(&:deactivate!)
   end
 
   def add_analytics
diff --git a/app/models/user.rb b/app/models/user.rb
index 94989f10..f385a69c 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -386,7 +386,7 @@ def deleted_skill?(skill_name)
 
 
   def tokenized_lanyrd_tags
-    lanyrd_facts.collect { |fact| fact.tags }.flatten.compact.map { |tag| Skill.tokenize(tag) }
+    lanyrd_facts.flat_map { |fact| fact.tags }.compact.map { |tag| Skill.tokenize(tag) }
   end
 
   def last_modified_at
@@ -426,11 +426,11 @@ def activity_stats(since=Time.at(0), full=false)
   end
 
   def upvoted_protips
-    Protip.where(id: Like.where(likable_type: "Protip").where(user_id: self.id).select(:likable_id).map(&:likable_id))
+    Protip.where(id: Like.where(likable_type: "Protip").where(user_id: self.id).pluck(:likable_id))
   end
 
   def upvoted_protips_public_ids
-    upvoted_protips.select(:public_id).map(&:public_id)
+    upvoted_protips.pluck(:public_id)
   end
 
   def followers_since(since=Time.at(0))
@@ -457,7 +457,7 @@ def score
   end
 
   def team_member_ids
-    User.select(:id).where(team_id: self.team_id.to_s).map(&:id)
+    User.where(team_id: self.team_id.to_s).pluck(:id)
   end
 
   def penalize!(amount=(((team && team.members.size) || 6) / 6.0)*activitiy_multipler)
@@ -677,19 +677,19 @@ def member_of?(network)
   end
 
   def following_users_ids
-    self.following_users.select(:id).map(&:id)
+    self.following_users.pluck(:id)
   end
 
   def following_teams_ids
-    self.followed_teams.map(&:team_id)
+    self.followed_teams.pluck(:team_id)
   end
 
   def following_team_members_ids
-    User.select(:id).where(team_id: self.following_teams_ids).map(&:id)
+    User.where(team_id: self.following_teams_ids).pluck(:id)
   end
 
   def following_networks_ids
-    self.following_networks.select(:id).map(&:id)
+    self.following_networks.pluck(:id)
   end
 
   def following_networks_tags
@@ -723,7 +723,7 @@ def is_mayor_of?(network)
   end
 
   def networks_based_on_skills
-    self.skills.collect { |skill| Network.all_with_tag(skill.name) }.flatten.uniq
+    self.skills.flat_map { |skill| Network.all_with_tag(skill.name) }.uniq
   end
 
   def visited!
diff --git a/app/models/users/github/followed_repo.rb b/app/models/users/github/followed_repo.rb
index cbce7789..9c73d73b 100644
--- a/app/models/users/github/followed_repo.rb
+++ b/app/models/users/github/followed_repo.rb
@@ -12,7 +12,7 @@ def description
       end
 
       def repo
-        data['link'].gsub('https://github.com/', '')
+        data['link'].sub('https://github.com/', '')
       end
 
       def date