title: firebase not defined Vue.js
body: <p>I'm new in vue.js and I'm learning vue.js from documentation and tutorial on internet, now I'm trying make app with Firebase and vue.js but my when I run it, an error says: </p>
  
  <p>-firebase not defined</p>
  
  <p>However, I'm pretty sure that I imported it. Here my code: </p>
  
  <p><strong>main.js:</strong></p>
  
  <pre><code>import Vue from 'vue'
  import App from './App'
  import router from './router'
  import * as firebase from "firebase"
  
  var config = {
   apiKey: "###########",
   authDomain: "###########",
   databaseURL: "###########",
   projectId: "###########",
   storageBucket: "###########",
   messagingSenderId: "###########"
  };
   firebase.initializeApp(config);
   Vue.config.productionTip = false
   /* eslint-disable no-new */
   new Vue({
    el: '#app',
    router,
    firebase,
    components: { App },
    template: '&lt;App/&gt;'
   })
  </code></pre>
  
  <p><strong>This my component register:</strong></p>
  
  <pre><code>&lt;template&gt;
  &lt;div class="login"&gt;
      &lt;h3&gt;Lets Register&lt;/h3&gt;
      &lt;input type="email" v-model="email"&gt;
      &lt;input type="password" v-model="password"&gt;
      &lt;button v-on:click="register"&gt;Submit&lt;/button&gt;
      &lt;p&gt;&lt;router-link to="/Login"&gt; Login? &lt;/router-link&gt;&lt;/p&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p></p>
  
  <pre><code>&lt;script&gt;
       export default {
       name: 'Register',
       data () {
          return{
              email: '',
              password: ''
          }
        },
       methods:{
          register : function(){
              firebase.auth().createUserWithEmailAndPassword(this.email,this.password).then(
                  function (user) {
                      alert('Account been created')
              },
              function(err){
                  alert('opps'+ err.message)
              }
                  );
              }
          }
      }
  </code></pre>
  
  <p></p>
  
  <p>Any help would be appreciated. </p>