sequelize/sequelize — pull request #2512 by jeff-french (2014-11-01 18:58:01+00:00)
Title: Fix for ENUM support in migration.addColumn with postgres dialect.

Incorrect sql was being generated when adding an ENUM column to an existing table using migrations:

```javascript
module.exports = {
up: function(migration, DataTypes, done) {
migration.addColumn('users', 'role', {
type: DataTypes.ENUM('user', 'staff', 'admin')
})
.complete(done);
}
};
```

was generating SQL like:

```sql
ADD COLUMN ('role', ENUM('user','staff','admin');
```

now produces:

```sql
ADD COLUMN ('role', 'enum_users_role');
```

Tests included.