Fix: CI.

[dblock]

A bit of matrix work post dc5118f to make it all work, and re-added Danger.

Dropped support for Mongoid 3, couldn't make it work.

Closes #78

[dblock]

@rmm5t all yours

[rmm5t]

[CONFUSED] ruby/setup-ruby supports a bundler option.

For example:

      - name: Set up Ruby
        uses: ruby/setup-ruby@v1
        with:
          ruby-version: ${{ matrix.ruby }}
          bundler: ${{ matrix.bundler }}

Why the extra work here to specify the bundler version? Also, for older ruby versions, just specify bundler 1.

[dblock]

I cannot get the older rubies + rails to work with anything other than bundler 2.0.0.pre.3. So I chose the version recommended. That said, I think I can do bundler: 2.0.0.pre.3, I didn't realize that was a setting.'

Update: ruby-setup doesn't support 2.0.0.pre.3 format, but this works with the latest 1.x. ruby/setup-ruby#439

[rmm5t]

[CONFUSED] I don't understand this refactor of the matrix. I'd rather see a traditional build matrix and possible include or exclude keys for edge cases.

i.e. This entry array doesn't make sense to me. What am I misunderstanding?

[dblock]

I find this a lot cleaner and more declarative because we benefit little from a matrix.

1. This is a 6x4 matrix and we should also be testing multiple MongoDB versions, so this will be 6x4x3 = 72 builds where about 75% are completely redundant. Even here, I started with a regular matrix and ended up with a long list of excludes, this avoids doing that.
2. For these older Rubies we need a different version of bundler (2.0.0.pre.3). This is yet another parameter then, matrix explodes.

[dblock]

My goal is get this back to green since dc5118f was merged without CI. Happy to accommodate whatever structure you prefer, lmk.

[dblock]

I find this a lot cleaner and more declarative because we benefit little from a matrix.

1. This is a 6x4 matrix and we should also be testing multiple MongoDB versions, so this will be 6x4x3 = 72 builds where about 75% are completely redundant. Even here, I started with a regular matrix and ended up with a long list of excludes, this avoids doing that.
2. For these older Rubies we need a different version of bundler (2.0.0.pre.3). This is yet another parameter then, matrix explodes.

[dblock]

I cannot get the older rubies + rails to work with anything other than bundler 2.0.0.pre.3. So I chose the version recommended. That said, I think I can do bundler: 2.0.0.pre.3, I didn't realize that was a setting.'

Update: ruby-setup doesn't support 2.0.0.pre.3 format, but this works with the latest 1.x. ruby/setup-ruby#439

[rmm5t]

Thanks for this. Sorry for the delay on the merge.