feature: external link on records

[adrianthedev]

Description

class Avo::Resources::Post < Avo::BaseResource
  # Show a link to the post outside Avo
  self.external_link = -> {
    main_app.post_path(record)
  }
end

It's pretty common to want to lead a user outside of Avo to the public path of a record.
This API enables that.

Still to do:

• tests
• docs
• figure out if we want to further configure second iteration
  • the label
  • the icon
  • the tooltip

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

Screenshots & recording

Manual review steps

1. Step 1
2. Step 2

Manual reviewer: please leave a comment with output from the test if that's the case.

[codeclimate]

Code Climate has analyzed commit ee80719 and detected 0 issues on this pull request.

View more on Code Climate.

[adrianthedev]

I'm open to naming suggestions