title: loopback.io get related result error thrown
body: <p>I have a <code>hasOne</code> relation between two models (<code>server</code> and <code>pool</code>) and I'm periodically updating the child via a cron.</p>
  
  <pre><code>Server.findOne({
      where:{
          id: 1
      }
  }, function(err, server) {
      if (err || !server) return next("Server not found");
      if (!_.isArray(pool)) return next("Invalid pool");
  
      server.pool(function(err, ip_pool){
          if(err) return next(err);
  
          if(ip_pool) {
              server.pool.destroy();
          }
  
          server.pool.create({
              pool: pool
          }, function(err) {
              next(err);
          });
      });
  });
  </code></pre>
  
  <p>The problem is that I get an error each time a new <code>pool</code> comes in stating: <code>TypeError: Object #&lt;ModelConstructor&gt; has no method 'pool'</code> which hits right on this line: <code>server.pool(function(err, ip_pool){</code>.</p>
  
  <p>I followed the docs but I can't seem to find out why this error is thrown.</p>