db: drop length limits on TEXT columns As of the upgrade to version 1.0 in 3c4b6ddf6735, SQLAlchemy began to pass TEXT length limits to the database during table creation. Such limits are however not supported by SQLite, MySQL nor PostgreSQL, and while SQLite simply ignores it, it is a syntax error in PostgreSQL, breaking the creation of new PostgreSQL databases. With the lengths being unused and quite arbitrary, just drop them.