\Phalcon\Db documentation issues

[slothentic]

I recently upgraded to 4.0.4 and have noticed a number of errors in the documentation here: https://docs.phalcon.io/4.0/en/db-layer#create-1

Most importantly, the second parameter schema for all db operations is null in the documentation, but that causes a fatal error.

For example:

PHP Fatal error:  Uncaught TypeError: Argument 2 passed to Phalcon\\Db\\Adapter\\AbstractAdapter::modifyColumn() must be of the type string, null given

I was able to fix this by simply passing "" an empty string as the second param.