Feature request: Pretty print migrations

[douglas-treadwell]

Is your feature request related to a problem? Please describe.

It's somewhat less convenient to read a long string of text for a migration with many columns. I'd prefer to be able to read the column definitions vertically.

Describe the solution you'd like

It would be more readable to have each column on its own line, like TypeORM's migration:generate --pretty flag.
Personally I would just make the pretty-printed version the default, unless whitespace causes problems with some DB drivers.

Describe alternatives you've considered
I'm planning to manually add line breaks to the generated migrations for now.

[B4nan]

No plans to do this, as it could introduce issues in executing the queries - most of the adapters require (by default) to have single statement on a single line. Also it is (for most queries) knex that generates them, and as far as I know, there is no "pretty" option for knex (for this very same reason).

What I can offer is a way to plug in custom migration generator class, so you could for example extend the one you are using now and format the query how you like it.