More advances on following-users
	modified:   app/controllers/relationships_controller.rb
	new file:   app/views/relationships/create.js.erb
	new file:   app/views/relationships/destroy.js.erb
	modified:   app/views/users/_follow.html.erb
	modified:   app/views/users/_unfollow.html.erb
	new file:   spec/controllers/relationships_controller_spec.rb