Revert "Install of angularJs"

This reverts commit d3de53d7a0e9c6ce223c514c1d092a9e170d543c.
display categories and create method to show newspapers by category
Merge branch 'experimental'

Conflicts:
	Gemfile
Add default categories in seeds.rb
delete migration news
Add default newspaper in seeds.rb
Cleaning up name of the app and Gemfile
Timezone pointing to Paris.
Fix CanCan ability.rb and make authorization effective to newspaper.
Begin the creation of a backend to link users to roles through a form.