title: async await callback is not a function
body: <p>I am using couchbase ottaman package:</p>
  
  <pre><code>let transaction = new Transaction({name:'Couch'});
      transaction.save((err) =&gt; {
          console.log(err);
      });
  </code></pre>
  
  <p>but can I use async/await with this package?</p>
  
  <pre><code>async create(){
          let transaction = new Transaction({name:'Couch'});
          try{
              await transaction.save();
          } catch (err) {
              console.log(err);
          }
      }
  </code></pre>
  
  <p>I am getting error:</p>
  
  <pre><code>node_modules\ottoman\lib\modelinstance.js:457
              callback(err);
              ^
  
  TypeError: callback is not a function
  </code></pre>