add eslint config

.eslintignore

@@ -0,0 +1,2 @@
+**/.eslintrc.js
+admin/words.js

.eslintrc.json

@@ -0,0 +1,42 @@
+{
+    "root": true,
+    "env": {
+        "es6": true,
+        "node": true,
+        "mocha": true
+    },
+    "extends": ["eslint:recommended"],
+    "plugins": [],
+    "rules": {
+        "indent": [
+            "error",
+            4,
+            {
+                "SwitchCase": 1
+            }
+        ],
+        "no-console": "off",
+        "no-unused-vars": [
+            "error",
+            {
+                "ignoreRestSiblings": true,
+                "argsIgnorePattern": "^_"
+            }
+        ],
+        "no-var": "error",
+        "no-trailing-spaces": "error",
+        "prefer-const": "error",
+        "quotes": [
+            "error",
+            "single",
+            {
+                "avoidEscape": true,
+                "allowTemplateLiterals": true
+            }
+        ],
+        "semi": ["error", "always"]
+    },
+    "parserOptions": {
+        "ecmaVersion": 2020
+    }
+}