Add eslint

.eslintrc.json

@@ -0,0 +1,28 @@
+{
+    "env": {
+        "es6": true,
+        "node": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "ecmaVersion": 2018
+    },
+    "rules": {
+        "indent": [
+            "error",
+            2
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "single"
+        ],
+        "semi": [
+            "error",
+            "never"
+        ]
+    }
+}

package.json

@@ -23,6 +23,7 @@
     "probot": "^7.2.0"
   },
   "devDependencies": {
+    "eslint": "^5.12.0",
     "jest": "^22.4.3",
     "nock": "^10.0.0",
     "nodemon": "^1.17.2",