Fix promise for node 10

Author: 0candy

lib/postgresql.js

@@ -15,6 +15,11 @@ var ParameterizedSQL = SqlConnector.ParameterizedSQL;
 var util = require('util');
 var debug = require('debug')('loopback:connector:postgresql');
 
+// Add support for node 0.10.x
+if (typeof Promise == 'undefined') {
+  global.Promise = require('promise');
+}
+
 /**
  *
  * Initialize the PostgreSQL connector against the given data source