title: Why am I getting "rawModule is undefined" when adding Vuex modules?
body: <p>I recently was struggling with implementing modules in Vuex for the first time. I couldn't find much info on the console error message I was getting ( <code>rawModule is undefined</code> ), so I thought I'd share the issue I ran into and the solution. I was doing a quick, simple version of a module implementation as I was working through some examples:</p>
  
  <pre><code>export const store = new Vuex.Store({
    state: {
      loggedIn: false,
      user: {},
      destination: ''
    },
    mutations: {
      login: state =&gt; state.loggedIn = true,
      logout: state =&gt; state.loggedIn = false,
      updateUser: ( state, user ) =&gt; { state.user = user },
      updateDestination: ( state, newPath ) =&gt; { state.destination = newPath }
    },
    modules: {
      project
    },
  });
  
  const project = {
    state: {}
  }
  </code></pre>