migrate to rails 4.2
update travis
remove inherited_resource from categories
Merge branch 'rails-4.2' of github.com:joseramonc/adminpanel into rails-4.2
:bug: remove extra scss extension
:green_heart: fix missing tests
:memo:
:fire: remove respond_to json
:lipstick:
Merge branch 'master' of github.com:joseramonc/adminpanel into rails-4.2
add benchmark tests for adequate record