fixed wrong single quote escaping for postgresql

lib/dialects/postgres/query-generator.js

@@ -15,7 +15,12 @@ function addQuotes(s, quoteChar) {
 
 
 function pgEscape(s) {
 function pgEscape(s) {
   s = Utils.escape(s)
   s = Utils.escape(s)
-  if (typeof s == 'string') s = s.replace(/\\"/g, '"')
+
+  if (typeof s == 'string') {
+    // http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS
+    s = s.replace(/\\'/g, "''")
+  }
+
   return s
   return s
 }
 }