title: Schema building with foreign keys
body: <p>I was wondering if someone could show me how to write the following <code>SQL</code> in <code>Laravel 4</code>Schema Builder`?</p>
  
  <pre><code>CREATE TABLE `conversation_reply` (
  `cr_id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,
  `reply` text,
  `user_id_fk` int(11) NOT NULL,
  `ip` varchar(30) NOT NULL,
  `time` int(11) NOT NULL,
  `c_id_fk` int(11) NOT NULL,
  FOREIGN KEY (user_id_fk) REFERENCES users(user_id),
  FOREIGN KEY (c_id_fk) REFERENCES conversation(c_id)
  );
  </code></pre>