Use pg callback over connection.release (#109)

Author: zbarbuto

lib/transaction.js

@@ -21,6 +21,7 @@ function mixinTransaction(PostgreSQL) {
     debug('Begin a transaction with isolation level: %s', isolationLevel);
     this.pg.connect(function(err, connection, done) {
       if (err) return cb(err);
+      connection.autorelease = done;
       connection.query('BEGIN TRANSACTION ISOLATION LEVEL ' + isolationLevel,
         function(err) {
           if (err) return cb(err);
@@ -63,9 +64,9 @@ function mixinTransaction(PostgreSQL) {
   };
 
   PostgreSQL.prototype.releaseConnection = function(connection, err) {
-    if (typeof connection.release === 'function') {
-      connection.release(err);
-      connection.release = null;
+    if (typeof connection.autorelease === 'function') {
+      connection.autorelease(err);
+      connection.autorelease = null;
     } else {
       var pool = this.pg;
       if (err) {