modify production.rb for heroku #4
modify .travis.yml to deploy heroku for #4
modify .travis.yml following travis-lint(help command for travis)
Merge pull request #46 from i-d-e-a-t/add-summer-sonic's-fes-page

Add summer sonic's fes page  ---->  master  ( ´∀｀)b
Merge pull request #39 from i-d-e-a-t/add-heroku-settings

Add heroku settings
modify api key
Merge pull request #54 from i-d-e-a-t/modify-heroku-settings

modify api key
added artist page
HTMLで記述されていた部分が残ってたので、slimに修正
modified:   app/views/artist/show.html.slim
refs  #40
* 不要なrequireを削除
* 不要な";"を削除
* URL設計の見直し(artist→artists)
* 埋め込みyoutubeのサイズを固定からウインドウ枠いっぱいを使うように変更

modified:   app/assets/stylesheets/artist.css.scss
modified:   app/controllers/artist_controller.rb
modified:   app/views/artist/show.html.slim
modified:   config/routes.rb
* URL設計の見直し(artists/:artist_id => artists/:path_key)

modified:   app/controllers/artist_controller.rb
Merge pull request #57 from i-d-e-a-t/add-artist-page

added artist page
Merge branch 'master' into add-navigation-to-top
#45 add navigation to top looks like 'cards'