Added a new best practices for custom form field types#5093

Merged

weaverryan merged 2 commits intosymfony:2.3from

javiereguiluz:fix_5077

Mar 24, 2015

Commits on Mar 19, 2015

Added a new best practices for custom form field types
javiereguiluz
committed
Fixed errors, typos and grammar issues. (I managed to fail at everything!)
javiereguiluz
committed