feat: add multiple option to attachment decorator

[guoyunhe]

Proposed changes

Sometimes we need to attach multiple files to a model, e.g. a job application may contain CV, cover letter, portfolio, copy of degree certificates, etc.

This PR add an multiple option to the decorator. Like this:

class User extends BaseModel {
  @attachment({ multiple: true })
  public photos: AttachmentContract[]
}

Types of changes

What types of changes does your code introduce?

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• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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• [x] I have read the CONTRIBUTING doc
• [ ] Lint and unit tests pass locally with my changes
• [x] I have added tests that prove my fix is effective or that my feature works.
• [x] I have added necessary documentation (if appropriate)

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[guoyunhe]

I am not able to run all the unit tests. Some tests failed with no details. The other tests don't even run...

[ndianabasi]

Hi @guoyunhe.

Thanks for your PR. Did you discuss with Virk if he would like this feature adopted before beginning the PR?

[guoyunhe]

@ndianabasi No.

[justDare]

This is SO damn useful, I hope you get permission + passing tests to get this added.

[thetutlage]

I think multiple attachments should be represented as multiple rows in the database. For example: I will rather have user_photos table and then give user the ability to delete or update each photo as a database row vs storing all photos in a single array.

So, for now I will skip this PR to keep the codebase simple :)