You commit changes to state in Vuex using defined
mutations. You can easily access these state mutations in your template using
mapMutations. This lesson shows you have to wire together your Vue.js template with your Vuex store using mutations and mapMutations.
I don't see how store/index.js is included into component. Shouldn't it be explicitly imported?
Is there any reason why we mutate over copy? Wouldn't copy be 'safer'?