Add instructions on how to set up code coverage backend

[mozilla]

Add instructions on how to set up code coverage backend

[armenzg]

@marco-c would you be able to verify the steps below?

Steps:

• Install the requirements
• On one terminal start the DB (./please run postgresql)
  • It could take several minutes
• On another terminal start the app (./please run shipit-uplift)
• Test that you can view all available APIs here

Once issue #17 is fixed we can point the frontend to a local instance of

[marco-c]

Currently, you will also need to create a TaskCluster client and pass client ID and access token as additional parameters to ./please run shipit-uplift like this: ./please run shipit-uplift --taskcluster-client-id=YOUR_CLIENT_ID --taskcluster-access-token=YOUR_ACCESS_TOKEN. This is a bit of a pain for new contributors and I hope we can remove this requirement soon (CC @La0, @garbas).

[armenzg]

If there's an issue would you mind pasting it here? I can't see it listed on the services repo.
Thanks!

[marco-c]

I filed mozilla/release-services#786.

[armenzg]

If anyone is interested to work on this they can try to fix mozilla/release-services#786 first.

[armenzg]

I'm closing this until it is taken care of in mozilla/release-services#786