Updates to Ruby 2.1.3 and Rails 4.1.6

[#25]
Merge pull request #26 from ChaeOkay/chaeokay/app_updates_ruby_2.1.3_rails_4.1.6

Updates to Ruby 2.1.3 and Rails 4.1.6
Adds courses/:id to router

[#20]
Writes a CourseRoute

[#20]
Removes blockers in ApplicationController
Writes api/courses#show

[#20]
Adds a log_in method

* And uses respond_with
[#20]
Adds imageUrl to course serializer / course model

[#20]
Writes course/:id template; links to courses template

[#20]
Removes imageHelper, which doesn't play nicely

* Foundation and Ember are fighting.
Adds expectation for course id
Merge pull request #27 from gschorkopf/gschorkopf/course_show

Gschorkopf/course_show
Adds ruby-version dot file
Removes .keep file
Writes api::users#create action

[#18]
Writes a simple user ember model
Writes the 'sign_up' route using ember form helpers
Removes more .gitkeep files