title: vue-resource http request gives:' _.isArray is not a function
body: <p>I'm trying to get an object from a server at <code>localhost:3000</code>. I can see the object when I go to the address in my browser. </p>
  
  <p>My front end runs this function defined in my <code>Vue</code> instance's <code>methods</code> property:</p>
  
  <pre><code>goToTutors: function(){
      this.step='tutors';
      this.$http.get('http://localhost:3000/tutors').then(
          function(tutors) {
              console.log("Tutors found!");
          },
          function(error) {
              console.log(error);
          });
  }
  </code></pre>
  
  <p>But in my browser's console, all I see is the error: </p>
  
  <blockquote>
    <p>Uncaught TypeError: _.isArray is not a function at vue-resource.js:172</p>
  </blockquote>
  
  <p>Can anyone point me to the cause of the error? </p>