Fix example in Vuex docs

doc/development/fe_guide/vue.md

@@ -507,6 +507,7 @@ This is the entry point for our store. You can use the following as a guide:
 import Vue from 'vue';
 import Vuex from 'vuex';
 import * as actions from './actions';
+import * as getters from './getters';
 import * as mutations from './mutations';
 
 Vue.use(Vuex);
@@ -514,6 +515,7 @@ Vue.use(Vuex);
 export default new Vuex.Store({
   actions,
   getters,
+  mutations,
   state: {
     users: [],
   },