Issue 3692 - Add base ESLint configuration

eslint-config-eyeo/README.md

+# eslint-config-eyeo
+
+An [ESLint](http://eslint.org) configuration that checks for compliance with the
+[Adblock Plus coding style guide](https://adblockplus.org/coding-style#javascript)
+which is used for all eyeo projects.
+
+## Installation
+
+    npm install -g eslint eslint-config-eyeo
+
+(As root, or using sudo.)
+
+## Usage
+
+To lint a JavaScript file using ESLint you simply run the `eslint` command with
+the file as an argument. For example:
+
+    eslint some-file.js
+
+(For advanced usage see `eslint --help`.)
+
+All of our projects which use much JavaScript should eventually have
+their own ESLint configuration which inherits from this base
+configuration. A minimal example:
+
+    {
+      "extends": "eslint-config-eyeo",
+      "root": true
+    }
+
+In the mean time if you need to lint files inside projects which do

[Sebastian Noack, 2017/02/12 20:53:11]

I don't like the duplication here. How about:

  In order to use eslint-config-eyeo,
  add following option to your .eslintrc.json
  (or put it in your ~/.eslintrc.json in order
  to lint projects that don't have an own
  configuration file):

(Or something along these lines) followed by the snippet.

[kzar, 2017/02/13 06:02:58]

OK, I've had another go. What do you think?

+not yet have an ESLint configuration you can create a personal
+configuration in `~/.eslintrc.json` like so:
+
+    {
+      "extends": "eslint-config-eyeo"
+    }