Adding Airbnb ESLint rules

Disable usupported rules for specific ember apps.
Add a eslint-config-airbnb-base, eslint-plugin-ember,
eslint-plugin-import to package.json.
Update ember-cli-code-coverage to v1.0.0-beta.4 version
to get the fix when using the `useBabelInstrumenter` config
see ember-cli-code-coverage/ember-cli-code-coverage#133 .

Closes #58

Author: bekicot

.eslintrc.js

@@ -10,12 +10,24 @@ module.exports = {
   ],
   extends: [
     'eslint:recommended',
-    'plugin:ember/recommended'
+    'plugin:ember/recommended',
+    'airbnb-base'
   ],
   env: {
     browser: true
   },
   rules: {
+    // This rule has no support for @ember import system.
+    // Ember build have their own mechanism to managing dependency.
+    // Ember build will raise error on build if there is an import error.
+    'import/extensions': 'off',
+    'import/no-unresolved': 'off',
+    'import/no-extraneous-dependencies': 'off',
+    // Ember use underscore dangling, e.g _super. Which is enforced by ember's
+    // own linter to be used on init() method.
+    'no-underscore-dangle': 'off',
+    // Ember Routes and tests utilize `this` inside their callback.
+    'prefer-arrow-callback': 'off',
   },
   overrides: [
     // node files

config/coverage.js

@@ -0,0 +1,7 @@
+/* global module */
+
+'use strict';
+
+module.exports = {
+  useBabelInstrumenter: true,
+};

package.json

@@ -43,6 +43,7 @@
     "ember-maybe-import-regenerator": "^0.1.6",
     "ember-source": "~3.1.0",
     "eslint": "^4.19.1",
+    "eslint-config-airbnb-base": "12.1.0",
     "eslint-plugin-ember": "^5.0.0",
     "eslint-plugin-import": "^2.7.0",
     "loader.js": "^4.2.3",

yarn.lock

@@ -3304,6 +3304,12 @@ escape-string-regexp@^1.0.2, escape-string-regexp@^1.0.5:
   version "1.0.5"
   resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
 
+eslint-config-airbnb-base@12.1.0:
+  version "12.1.0"
+  resolved "https://registry.yarnpkg.com/eslint-config-airbnb-base/-/eslint-config-airbnb-base-12.1.0.tgz#386441e54a12ccd957b0a92564a4bafebd747944"
+  dependencies:
+    eslint-restricted-globals "^0.1.1"
+
 eslint-import-resolver-node@^0.3.1:
   version "0.3.2"
   resolved "https://registry.yarnpkg.com/eslint-import-resolver-node/-/eslint-import-resolver-node-0.3.2.tgz#58f15fb839b8d0576ca980413476aab2472db66a"
@@ -3326,8 +3332,8 @@ eslint-plugin-ember@^5.0.0:
     snake-case "^2.1.0"
 
 eslint-plugin-import@^2.7.0:
-  version "2.13.0"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.13.0.tgz#df24f241175e312d91662dc91ca84064caec14ed"
+  version "2.12.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.12.0.tgz#dad31781292d6664b25317fd049d2e2b2f02205d"
   dependencies:
     contains-path "^0.1.0"
     debug "^2.6.8"
@@ -3340,6 +3346,10 @@ eslint-plugin-import@^2.7.0:
     read-pkg-up "^2.0.0"
     resolve "^1.6.0"
 
+eslint-restricted-globals@^0.1.1:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/eslint-restricted-globals/-/eslint-restricted-globals-0.1.1.tgz#35f0d5cbc64c2e3ed62e93b4b1a7af05ba7ed4d7"
+
 eslint-scope@^3.7.1:
   version "3.7.1"
   resolved "https://registry.yarnpkg.com/eslint-scope/-/eslint-scope-3.7.1.tgz#3d63c3edfda02e06e01a452ad88caacc7cdcb6e8"