title: get Selected fields in .populate() waterline-postgresql .populate('fieldName',{select:[]})
body: <p>select query is not working in .populate() of waterline-postgresql. </p>
  
  <pre><code>Model.find(query).populate(assoc.alias,{select:['field1','field2']});
  </code></pre>
  
  <p>This is not working in waterline-postgresql adapter.</p>
  
  <p>Is this not supported or Am I making any mistake?</p>