precompileのためにファイルを削除
Gemfile: rails_12factorを追加
mend
prepare seed file, modify schema
modify migration file
update Gemfile
modify Gemfile
gem install execjs
specicy bootswatch version 3.0.0
rake assets:precompile
swith over to Ruby 2, Rails4
precompile without Makefile of WaveSurfer