fixed issue #67 - add support for JSON type

Author: matmar10

lib/migrate.js

@@ -44,6 +44,7 @@ const reverseSequelizeColType = function(col, prefix = 'Sequelize.')
         case DataTypes.REAL.key:
         case DataTypes.DOUBLE.key:
         case DataTypes.DECIMAL.key:
+        case DataTypes.JSON.key:
         case DataTypes.INTEGER.key: {
             let ret = attrName;
             if (options.length)