Add ESLint config file

.eslintrc.json

@@ -0,0 +1,57 @@
+{
+  "env": {
+    "browser": true,
+    "es6": true
+  },
+  "extends": "eslint:recommended",
+  "parserOptions": {
+    "sourceType": "module"
+  },
+  "rules": {
+    "no-console": [
+      "off"
+    ],
+    "indent": [
+      "error",
+      2
+    ],
+    "linebreak-style": [
+      "error",
+      "unix"
+    ],
+    "quotes": [
+      "error",
+      "single"
+    ],
+    "semi": [
+      "error",
+      "always"
+    ],
+    "space-before-function-paren": [
+      "error",
+      {
+        "anonymous": "always",
+        "named": "never"
+      }
+    ],
+    "brace-style": [
+      "error",
+      "stroustrup"
+    ],
+    "keyword-spacing": [
+      "error",
+      {
+        "after": true
+      }
+    ],
+    "no-unused-vars": [
+      "off"
+    ],
+    "no-undef": [
+      "off"
+    ],
+    "space-before-blocks": [
+      "error"
+    ]
+  }
+}