Lint scripts in markdown files

To prevent backticks and errors in example code.

Also fix typo in example code.

Fixes #13

Author: maoberlehner

.eslintrc-md.json

@@ -0,0 +1,10 @@
+{
+  "plugins": ["markdown"],
+  "extends": ".eslintrc",
+  "rules": {
+    "quotes": [2, "single", { "avoidEscape": true }],
+    "import/extensions": false,
+    "import/no-extraneous-dependencies": false,
+    "import/no-unresolved": false
+  }
+}

README.md

@@ -302,7 +302,7 @@ By default, mutations and getters inside modules are registered under the global
 import Vue from 'vue';
 import Vuex from 'vuex';
 
-import { getField, updateFiled } from 'vuex-map-fields';
+import { getField, updateField } from 'vuex-map-fields';
 
 Vue.use(Vuex);