Option for adding custom validation codes

[MartinElvar]

What problem does this feature solve?

Currently all custom changeset results in ecto.changeset.unknow, which is problematic to make sense for a client.

What is your proposed solution?

A solution could be to add a custom module, that straw_hat will try and match validation errors against.

[yordis]

@MartinElvar do you need help with this or could you make a PR? Otherwise, just add some example code on how you would like the API to look like.

[yordis]

Btw quick question,

Are you using one of these https://github.com/straw-hat-team/straw_hat/blob/a892754ac67568d4c6d7eb77fd83ceac5098a767/lib/straw_hat/error/changeset_parser.ex#L56-L60 ?

Because I remember that we should add either validation or constraint key to the custom error.

I fixed this in Ecto and we should encourage adding that key to libraries and definitely add it if you control the code.

[yordis]

@MartinElvar is this still relevant to you?