title: ParseUser : Cannot use object of type __PHP_Incomplete_Class as array
body: <p>I want to use Parse to save data.<br>
  I use ParseUser to save users.<br>
  Documentation <a href="https://parse.com/docs/php/guide#users" rel="nofollow">here</a>.    </p>
  
  <p>When I make this I have a ParseUser object : </p>
  
  <pre><code>    $user = new \Parse\ParseUser();
      $user-&gt;set("username", "my name");
      $user-&gt;set("password", "my pass");
      $user-&gt;set("email", "email@example.com");
      var_dump($user);
      exit();
  </code></pre>
  
  <p>But if I try to use signUp method.<br>
  Documentation <a href="https://www.parse.com/docs/php/guide#users-signing-up" rel="nofollow">here</a>.</p>
  
  <p>Like this : </p>
  
  <pre><code>        $user = new \Parse\ParseUser();
      $user-&gt;set("username", "my name");
      $user-&gt;set("password", "my pass");
      $user-&gt;set("email", "email@example.com");
  
      try {
          $user-&gt;signUp();
      } catch (\Parse\ParseException $ex) {
          echo $ex-&gt;getMessage();
      }
  
      exit();
  </code></pre>
  
  <p>I have this message : </p>
  
  <blockquote>
    <p>object(__PHP_Incomplete_Class)#1 (11) { ["__PHP_Incomplete_Class_Name"]=> string(15) "Parse\ParseUser" ["_sessionToken":protec.....
    Fatal error: Cannot use object of type __PHP_Incomplete_Class as array in /var/www/myproject/vendor/parse/php-sdk/src/Parse/ParseUser.php on line 340</p>
  </blockquote>