Add rubygem scope to API key create API endpoint

[jenshenny]

Adds onto: #2944

Adds support to scope an API key to a gem when creating an API key through the API. This will be used when the user runs gem signin.

How is this implemented?

Added a rubygem_name param to API key create. During gem signin, the client asks for the name of the gem.

...
Enter the name of the gem you want to scope this key to (strongly recommended).
Gem Scope [All gems]: rails
...

CLI PR: rubygems/rubygems#5710

Alternatives

I thought about having the user select from a list of their gems but it's difficult to display correctly if the user has many gems. Furthermore, the only endpoint that returns the gems someone owns requires an API key with the index_rubygems scope which can't work because the command is creating an API key. So if we were going to go down this path, we would need to allow for basic auth to the endpoint instead.

Other Notes

I omitted adding the rubygem_name param to update for now as assign_attributes autosaves associations and "half saves" the api key if validations fail. I have a branch with a monkey patch for it but I want to spend more time figuring out if there's a better way. Nonetheless, the update endpoint won't be used for gem signin.

Testing

1. Create or have a user on hand
2. Have the user own a gem (Rubygem.create(name: "a-gem"), Ownership.create_confirmed(Rubygem.find_by_name("a-gem", User.first, User.first)
3. Run RUBYGEMS_HOST=http://localhost:3000 ruby -Ilib bin/gem signin in the rubygems directory
4. Enable one or more of the applicable scopes (add/yank rubygems, add/remove owner) and you will see a gem scope prompt. Enter the name of the gem that the owner owns and the created API key should have the scope
5. Do step 4 again (should gem signout) and type something else, an error will return as the owner doesn't own a gem named that and an API key would not be created.
6. Do step 4 again and enable one of the other scopes (eg. index_rubygems) and you will not see a gem scope prompt.

[simi]

@jenshenny any idea how to move this forward? 🤔

[jchestershopify]

@jenshenny is out for the next week. I'm not sure where we got to on this but it looks like we'd need to do a fair amount of rebasing.

[jenshenny]

Thanks for pinging me on this, it fell off my radar. At the point in time in which the PR was opened, it was ready for review. I'll rebase this PR and the RubyGems one rubygems/rubygems#5710 to get it up to date and make sure the changes make sense. Afterwards, I'll request some reviews!

[codecov]

Codecov Report

Merging #3136 (c51be12) into master (d601df0) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3136   +/-   ##
=======================================
  Coverage   98.77%   98.77%           
=======================================
  Files         209      209           
  Lines        5135     5139    +4     
=======================================
+ Hits         5072     5076    +4     
  Misses         63       63           

Impacted Files	Coverage Δ
app/controllers/api/v1/api_keys_controller.rb	100.00% <100.00%> (ø)
app/models/api_key.rb	100.00% <100.00%> (ø)

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[simi]

:)

[simi]

I'm sorry for such a long time without review.

[kevinlinxc]

We did it! 😊