Add ESLint for this project

.eslintrc.json

@@ -0,0 +1,22 @@
+{
+  "root": true,
+  "parserOptions": {
+    "ecmaVersion": 6
+  },
+  "env": {
+    "browser": true,
+    "es6": true,
+    "webextensions": true
+  },
+  "extends": [
+    "eslint:recommended"
+  ],
+  "rules": {
+    "no-console": 0,
+    "no-unused-vars": ["warn", { "vars": "all", "args": "all" } ],
+    "no-undef": ["warn"],
+    "no-proto": ["error"],
+    "prefer-arrow-callback": ["warn"],
+    "prefer-spread": ["warn"]
+  }
+}

package.json

@@ -0,0 +1,15 @@
+{
+  "name": "webextensions-examples",
+  "version": "1.0.0",
+  "description": "",
+  "devDependencies": {
+    "eslint": "^3.19.0"
+  },
+  "scripts": {
+    "lint": "eslint ."
+  },
+  "license": "MIT",
+  "dependencies": {
+    "babel-eslint": "^7.2.3"
+  }
+}