add mongo, carrierwave to upload files
add mongo, carrierwave to upload files
user can add custom buttons
Merge branch 'feature-upload_files' of github.com:bernardogalindo/botonera-game into feature-upload_files

Conflicts:
	Gemfile
	Gemfile.lock
	botonera.rb
	views/index.haml
	views/new_button.haml
Merge branch 'feature-upload_files'