added eslint and prrettier config files

backend/.eslintrc.json

@@ -0,0 +1,40 @@
+{
+  "env": {
+    "es2021": true,
+    "node": true
+  },
+  "extends": [
+    "airbnb-base",
+    "plugin:@typescript-eslint/recommended",
+    "prettier/@typescript-eslint",
+    "plugin:prettier/recommended"
+  ],
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "ecmaVersion": 12,
+    "sourceType": "module"
+  },
+  "plugins": ["@typescript-eslint", "prettier"],
+  "rules": {
+    "prettier/prettier": "error",
+    "import/extensions": [
+      "error",
+      "ignorePackages",
+      {
+        "ts": "never"
+      }
+    ],
+    "quotes": [
+      1,
+      "double",
+      {
+        "avoidEscape": true
+      }
+    ]
+  },
+  "settings": {
+    "import/resolver": {
+      "typescript": {}
+    }
+  }
+}