[feature/course-management] Add full course management
[feature/course-management] Cleaning views and adding bootstrap
[feature/tags-categories-management] Manage tags and categories features
[feature/course-management] Add duration column to courses
[fix/course-duration] Fix regex duration and add meta tags layout
[feature/course-management] Update user list's button name. Yeah.
[feature/course-management] Fix update tags and categories
[feature/course-management] Add full JSON API
[feature/course-management] Fix participation and tagging cascade destroy
split for integratio
[feature/course-management] Add full user roles and permissions
[feature/course-management] Fix show user action index
[feature/gravatar] Add gravatar for index
feature/integration: home integration
[feature/gravatar] Formatting gravatar images and adding top right user link
[fix/role-new-user] fix user role default
feature/integration/merge & fix
[feature/first-release-ruby-work] merge & fix feature/integration
Merge branch 'feature/integration' into feature/first-release-ruby-work
[feature/first-release-ruby-work] merge and fix user gravatar in navbar