Added options to beginTransaction

Author: rathreya

lib/transaction.js

@@ -19,7 +19,14 @@ function mixinTransaction(PostgreSQL) {
    * @param isolationLevel
    * @param cb
    */
-  PostgreSQL.prototype.beginTransaction = function(isolationLevel, cb) {
+  PostgreSQL.prototype.beginTransaction = function(isolationLevel, options, cb) {
+
+    if ((!cb) && typeof options === 'function') {
+      cb = options;
+      options = {};
+    }
+    options = options || {};
+
     const connector = this;
     debug('Begin a transaction with isolation level: %s', isolationLevel);
     this.pg.connect(function(err, connection, done) {