Implementing passing AC/WA info using flash.
Add mongoid-paperclip plugin and generate Image model

Conflicts:
	config/routes.rb
Add image uploading function

Conflicts:
	app/views/contests/problems/_form.html.erb
	config/routes.rb
Add message methods to Problem model
Add a message to flash[:solved] according to AC/WA
Display AC/WA message in problem page after submission
Make message methods instance methods to make them more flexible
Remove unused file
Change <br /> to <br>
Make the View responsible for, well, the view.
Merge pull request #53 from TakenokoChocoHolic/25_modern_line_break

Change <br /> to <br>
Merge branch 'master' into 23_image_uploader

Conflicts:
	app/views/contests/problems/_form.html.erb
Update README.md
Merge pull request #50 from TakenokoChocoHolic/23_image_uploader

23 image uploader
Merge pull request #51 from TakenokoChocoHolic/2_Show_ACWA

2 show acwa
Merge branch 'master' into rich_timepicker_ui
Repalce <br /> with <br>

Conflicts:
	app/views/contests/_form.html.erb