Add .eslintrc file

[ismyrnow]

I think I'll do a PR for one that's already in an existing project, and then we can fill it out further.

[ismyrnow]

I forgot I have write permissions. I just created a commit (edfde8b) with a new file. A good first step might be translating the jshint rules we have to eslint.

[knownasilya]

Looks like there's a addon for ember as well https://github.com/jonathanKingston/ember-cli-eslint, although looks like you have to use the babel parser, for the es2015 syntax.

[ismyrnow]

I wrote a CLI around a tool I found to map jshint to eslint files. However, I'm not confident that it's producing valuable output.

https://github.com/ismyrnow/eslint-rules-mapper

I updated the eslint file (a01bb05) based on the output, and made a few manual edits as well. It's probably worth spending a developers lunch going through the list and building a more complete version of this.

Maybe it's also worth specifying all values, including defaults, since you generally have to read the docs to see what the defaults are. They're not always intuitive, because the rules aren't all boolean.