Use ace editor as gem

Gemfile

Gemfile.lock

app/assets/javascripts/application.js

app/views/projects/edit_tree/show.html.haml

vendor/assets/javascripts/ace-src-noconflict/ace.js

...assets/javascripts/ace-src-noconflict/keybinding-emacs.js

...r/assets/javascripts/ace-src-noconflict/keybinding-vim.js

...or/assets/javascripts/ace-src-noconflict/mode-c9search.js

vendor/assets/javascripts/ace-src-noconflict/mode-c_cpp.js

vendor/assets/javascripts/ace-src-noconflict/mode-clojure.js

vendor/assets/javascripts/ace-src-noconflict/mode-coffee.js

.../assets/javascripts/ace-src-noconflict/mode-coldfusion.js

vendor/assets/javascripts/ace-src-noconflict/mode-csharp.js

vendor/assets/javascripts/ace-src-noconflict/mode-css.js

vendor/assets/javascripts/ace-src-noconflict/mode-diff.js

vendor/assets/javascripts/ace-src-noconflict/mode-glsl.js

vendor/assets/javascripts/ace-src-noconflict/mode-golang.js

vendor/assets/javascripts/ace-src-noconflict/mode-groovy.js

vendor/assets/javascripts/ace-src-noconflict/mode-haxe.js

vendor/assets/javascripts/ace-src-noconflict/mode-html.js