Configuration which let us skip 'FactoryGirl' during build,create, etc.
Add new model course_learners as table for many-to-many association between user and course
Add tests to check association between user and course
Add readable stylesheets from bootswatch
Create association for two cases: User has many courses as an author and has_many courses as a student
Create association for two cases: Course has many students and has_one author
Add link under logo to root path
Use content_for to show header if user is signed in
Add yield for head to display content_for(:head)
Add seed for 10 new users
Capitalize name of City before save
Add simple css to set header
Add annotate comments