SQL migrations

Hey, just created simple SQL migrations for Phalcon if somebody prefers this method of database migrations.

Feel free to use https://github.com/davihu/phalcon-ext

Sample migration example

use PhalconExt\Db\SqlMigrations\AbstractMigration;

class Migration160910160944 extends AbstractMigration
{
    public function up()
    {
        $this->addSql("ALTER TABLE robots ADD COLUMN number VARCHAR(20)");
        $this->addSql("...");
    }

    public function down()
    {
        $this->addSql("ALTER TABLE robots DROP COLUMN number");
        $this->addSql("...");
    }
}