CURRENT_TIMESTAMP not quoted even for non-datetime columns #1891
Description
The following code will throw an error:
$this->table('test')
->addColumn('test_col', 'string', ['default' => 'CURRENT_TIMESTAMP'])
->create();This is because the default value will not be quoted. We can probably update the if check for CURRENT_TIMESTAMP either apply if the column type is a datetime/timestamp, or not if the column is a string. I would probably lean towards doing the former, and then for custom types, the user will just be expected to use a Literal, as the latter does not really leave a good way for a user to handle custom types satisfactorily.