title: Computed property was assigned to but it has no setter
body: <p>What is the correct syntax/hooks to make this work for myVal?</p>
  
  <p>My code looks like this:</p>
  
  <pre><code>&lt;v-item-group v-model="myVal" ...
  
  import { mapActions, mapGetters } from 'vuex'; 
  export default {
    computed : {
       ...mapActions({
         myVal: 'myModulePath/setMyVal'
       }),
       ...mapGetters({
         myVal: 'myModulePath/getMyVal'
       }),
    },
  }
  </code></pre>
  
  <p>The store looks like:</p>
  
  <pre><code>actions: {
    setMyVal({commit}, value){commit('someMutation',value);}
  getters: {
    getMyVal: state =&gt; { return state.myVal;}
  </code></pre>
  
  <p>I'm not sure how to wire it so the 'setter' works and the error message goes away.</p>
  
  <p>I've also tried this to no avail:</p>
  
  <pre><code>...mapState('myModulePath', ['myVal']) 
  </code></pre>