Add analyzer for leap

[kytrinyx]

We have some logic in the leap test suite that ensures that people don't use the built-in functions from Date.

Since the instructions don't say anything about not using built in functions (see https://github.com/exercism/ruby/blob/main/exercises/practice/leap/.docs/instructions.md), we should create an analyzer for this functionality.

[kotp]

Alternative middle step may be the add the mention in the documentation, as an append.

I would be as delighted, though, to see a refinement on the Date class, as much as a "not Date class" solution. I believe an analyzer could detect if the built in method from Date is used, but the tests likely can not.

[kytrinyx]

Alternative middle step may be the add the mention in the documentation, as an append.

That would work, too.

I would be as delighted, though, to see a refinement on the Date class, as much as a "not Date class" solution. I believe an analyzer could detect if the built in method from Date is used, but the tests likely can not.

Agreed. I think an analyzer would be a really nice improvement for this exercise.