Appreciate for the work of this project.

I know it seems rule to ask for such feature and maybe it is "impossible" to implement. But, how if user provides directories structure in _sidebar.md file.

for example _sidebar.md

- FolderName
  - [Article1](/FolderName/Article1.md)
  - [Article2](/FolderName/Article2.md)
- FolderName2
  - [Article3](/FolderName2/Article3.md)
  - [Article4](/FolderName2/Article4.md)

The original demand comes from that i want to construct my personal blog with doscify. However, the sidebar is as long as my article amount.

I found that i can write a bash script to help me scan my folders and then generate a sidebar file. such as
find . -mindepth 2 -name "*.md" | awk -F'/' 'BEGIN {RS=".md"} {arr[$2]=arr[$2]"\n - ["$3"](/"$2"/"$3")"} END {for (key in arr) print "- "key, arr[key]}' > _sidebar.md
what's more, travis ci can help us do such a job.

so, can docsify add a toggle feature for no hyperlink item in the sidebar? it is ok for adding it into configurable options.