Allow admins to edit assigned volunteers on edit casa_case page

[colinsoleim]

What github issue is this PR for, if any?

Resolves #90

Checklist

• I have performed a self-review of my own code
• I added comments, particularly in hard-to-understand areas
• I updated the /docs
• I added tests that prove my fix is effective or that my feature works
• bundle exec rake passes locally
• My PR title includes "WIP" or is draft PR if work is in progress

What changed, and why?

This PR gives admins the ability to assign and unassign volunteers on the existing edit_casa_case view.

How will this affect user permissions?

Only admins can access the new page

How is this tested?

New tests have been added and local testing

Screenshots please :)

[compwron]

Nice! Thanks :) 💖🚀

[compwron]

it looks like the build is failing with:

Failure/Error: expect(page.all("table#volunteers tr").count).to eq 4
     
       expected: 4
            got: 6

That's probably just the new UI element showing up in an unspecific page search

[colinsoleim]

it looks like the build is failing with:

Failure/Error: expect(page.all("table#volunteers tr").count).to eq 4
     
       expected: 4
            got: 6

That's probably just the new UI element showing up in an unspecific page search

I think there may be an issue with Javascript on Travis? In its previous state, this test was passing on Travis but failing for me locally. This new version is passing for me locally, but failing here.

By default the dashboard page should only be showing the "Active" volunteers, so it should hide the 2 "inactive" volunteers, but it looks like it is showing everything for some reason.

[colinsoleim]

it looks like the build is failing with:

Failure/Error: expect(page.all("table#volunteers tr").count).to eq 4
     
       expected: 4
            got: 6

That's probably just the new UI element showing up in an unspecific page search

Yeah I just edited the test, and it's still failing even after the initial expect was removed. It looks like the jquery datatable filtering isn't working on Travis for some reason. I'll look into it now.

[colinsoleim]

Looks like there was an error with this test after we tried debugging some of the issues with the Heroku CSS. For some reason, upgrading some of the npm packages caused the issue, might have to be careful with that in the future in case we do have to upgrade. I reverted the versions for now, and everything appears to be fixed.

[compwron]

Thanks!!
Argh