Improve code styling (#23)

* Typescript eslint added to the package.json

* Code review

.eslintrc.json

@@ -0,0 +1,20 @@
+{
+    "env": {
+        "browser": true,
+        "es2021": true
+    },
+    "extends": [
+        "eslint:recommended",
+        "plugin:@typescript-eslint/recommended"
+    ],
+    "parser": "@typescript-eslint/parser",
+    "parserOptions": {
+        "ecmaVersion": 12,
+        "sourceType": "module"
+    },
+    "plugins": [
+        "@typescript-eslint"
+    ],
+    "rules": {
+    }
+}

package.json

@@ -27,17 +27,24 @@
     "watch-ts": "tsc -w",
     "watch-node": "nodemon dist/app.js",
     "watch": "concurrently -k -p \"[{name}]\" -n \"TypeScript, Node\" -c \"yello.bold, cyan.bold\" \"yarn run watch-ts\" \"yarn run watch-node\"",
-    "docs": "apidoc -i src/ -o public/apidoc/"
+    "docs": "apidoc -i src/ -o public/apidoc/",
+    "lint": "yarn eslint --ext .js,.ts,.tsx src/** test/**"
   },
   "devDependencies": {
     "@types/chai": "^4.1.5",
     "@types/mocha": "^5.2.5",
     "@types/mongoose": "^5.2.17",
     "@types/nock": "^9.3.0",
+    "@typescript-eslint/eslint-plugin": "^4.6.0",
+    "@typescript-eslint/parser": "^4.6.0",
     "chai": "^4.2.0",
+    "eslint": "^7.12.1",
+    "eslint-plugin-import": "^2.22.1",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-promise": "^4.2.1",
     "mocha": "^5.2.0",
     "nock": "^10.0.0",
     "ts-node": "^7.0.1",
-    "typescript": "^3.1.1"
+    "typescript": "^4.0.5"
   }
 }