Allow using shorthand types in other shorthands

[tshelburne]

For example:

exports.shorthands = {
  ref: {type: `integer`, onDelete: `cascade`},
  user: {type: `ref`, references: `users`},
}

This also currently doesn't work if the shorthand was defined in an earlier migration file.

[dolezel]

Hmm, it can be to complicated and can lead to cyclic definition.
I can suggest to use

const ref = {type: `integer`, onDelete: `cascade`}
exports.shorthands = {
  ref,
  user: { ...ref, references: `users`},
}

[tshelburne]

If I submitted a PR that checked for a cyclic definition would you consider it?

[dolezel]

Sure, you can look on it :)

[dolezel]

Got some time to look on it ;-)

[tshelburne]

Oh wow, that was fast. I'm used to tickets lasting for a little while.

Thanks!