Added users to federation

[Skarlso]

Summary

Adds users to Federation.

Related to #4.

[Skarlso]

something wrong with the linter again :/

[yitsushi]

  Error: 1-60 lines are duplicate of `services/federation/users_test.go:1-61` (dupl)
  Error: 1-61 lines are duplicate of `services/federation/instances_test.go:1-60` (dupl)

[yitsushi]

rebase from main, i added a golangci configuration file to ignore dupl (and a few others) in tests.

[yitsushi]

The linter works as intended (ignore all the tar errors, not an issue, hope the will fix it, but it's there even if the PR passes the check. Scroll down and check teh results instead of all the tar errors. Fixed.

And you can always run the linter locally.

[yitsushi]

Please update the README too as this PR resolves #4

[coveralls]

Coverage increased (+0.7%) to 65.353% when pulling b1b251b on Skarlso:federation_v5 into cf0ecd5 on yitsushi:main.