Fix invalid "USING" order in Postgres query generator

lib/dialects/postgres/query-generator.js

@@ -435,8 +435,8 @@ module.exports = (function() {
 
       return Utils._.compact([
         "CREATE", options.indicesType, "INDEX", this.quoteIdentifiers(options.indexName),
-        (options.indexType ? ('USING ' + options.indexType) : undefined),
-        "ON", this.quoteIdentifiers(tableName), '(' + transformedAttributes.join(', ') + ')'
+        "ON", this.quoteIdentifiers(tableName), (options.indexType ? ('USING ' + options.indexType) : undefined),
+        '(' + transformedAttributes.join(', ') + ')'
       ]).join(' ')
     },