Hi there,
https://www.spark.io/build is really great IDE, but some of you may want to use other editors, for me it’s Emacs
I summarized how to setup Emacs & command line tools at http://d.hatena.ne.jp/higepon/20140912/1410528195.
I hope it will help you guys.
And please feel free to share your Emacs tips here. Thanks!