Add some docs on application helper
Add some docs on application helper

[ci skip]
munirent/filepicker-rails,munirent/filepicker-rails,SchoolKeep/filepicker-rails,Ink/filepicker-rails,Ink/filepicker-rails,SchoolKeep/filepicker-rails,Ink/filepicker-rails,munirent/filepicker-rails,SchoolKeep/filepicker-rails