Initial Commit.
Add model for user & use 'devise' gem for user management.
Adding bootstrap.
update Gemfile.lock.
Add the skeleton workflow for welcome, about, login, logout, etc.
fix bootstrap bug.
Update registration form.
Setup core tables: course, role, enrollment.
Set up ACL ability. Admin can create courses now.
Merge pull request #1 from manhhung741/add_role_and_authorization

Add role and authorization
Update README
Make ui responsive.
Add assignment model. Update view to use bootstrap style.
Add model for Question & Answer.
Update associations between models. Correct the name of creator_id column in answer and course_id column in course.
Fix crud for assignments and courses. Next is to update UI.
Merge pull request #2 from manhhung741/CRUDS

Fix crud for assignments and courses. Next is to update UI.
Add logo_url and banner_url to courses table.
update page structure.
add user_course relation when creating course. list the courses in home view.