title: $emit doesn't trigger child events
body: <p>For a VueJS 2.0 project I have the following on the parent component</p>
  
  <pre><code>&lt;template&gt;
  &lt;child&gt;&lt;/child&gt;
  &lt;button @click="$emit('childEvent)"&gt;&lt;/button&gt;
  &lt;/template&gt;
  </code></pre>
  
  <p>on the child component I have: </p>
  
  <pre><code>{
    events: { 'childEvent' : function(){.... },
    ready() { this.$on('childEvent',...) },
    methods: { childEvent() {....} }
  }
  </code></pre>
  
  <p>Nothing seems to work on button click. Is it that I need to create a parent method that would then emit to the child? I was using vuejs 1. but now I'm confused as to the ways parent to child communications work</p>