eslint rules updated

.eslintrc.json

@@ -14,11 +14,12 @@
       "warn",
       "double"
     ],
-    "no-tabs": "off",
+    "no-tabs": "error",
     "indent": [
       "warn",
       4
     ],
+    "no-var": "error",
     "eol-last": ["error", "always"],
     "react/jsx-uses-react": "error",
     "react/jsx-uses-vars": "error"