fix(postgres/query-generator): fix issue introduced by missing pgDataTypeMapping…

… in changeColumnQuery

lib/dialects/postgres/query-generator.js

@@ -212,8 +212,8 @@ module.exports = (function() {
           });
         }
 
-        if (definition.match(/^ENUM\(/)) {
-          query = this.pgEnum(tableName, attributeName, definition) + query;
+        if (attributes[attributeName].match(/^ENUM\(/)) {
+          query = this.pgEnum(tableName, attributeName, attributes[attributeName]) + query;
           definition = definition.replace(/^ENUM\(.+\)/, this.quoteIdentifier('enum_' + tableName + '_' + attributeName));
           definition += ' USING (' + this.quoteIdentifier(attributeName) + '::' + this.quoteIdentifier(definition) + ')';
         }