title: Access to vue root instance in vuex module action
body: <p>According to github accessing the vue root instance is quite easy in actions.</p>
  
  <p><a href="https://github.com/vuejs/vuex/issues/1399" rel="nofollow noreferrer">https://github.com/vuejs/vuex/issues/1399</a></p>
  
  <p>I've tested it ant it works. This is my store setup:</p>
  
  <pre><code>export default new Vuex.Store({
      actions: {
          testPieter (context) {
              console.log('this in testpieter', this)
              console.log('vm in testpieter', this._vm)
          }
      },
      modules: {
        userStore,
        notifications,
        safetyDrone
    },
    strict: debug
  })
  </code></pre>
  
  <p>Problem is, in the actions in the modules I can't seem to access the vue instance, when i console.log the store from the action:</p>
  
  <p><a href="https://i.stack.imgur.com/3Kaop.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3Kaop.png" alt="enter image description here"></a></p>
  
  <p>when i console.log(this) from the action i just get the exports defined in the module file..</p>
  
  <p>Is there a built-in/elegant way to access the vue root instance?</p>