Add the link of your merge request to a youtrack ticket. If you're on branch feat/ABC-956, it'll look for the ticket ABC-956 and add the link to the merge request on the comments of the ticket.
You'll need Go installed on your machine.
Clone the repository.
Rename .env.example to .env, and fill it with a gitlab token, a youtrack token and your youtrack URL (example: https://example.youtrack.cloud).
Compile the project (go build).
Put it somewhere in your path (I use .local/bin).
In a git repo, on branch feat/ABC-956 that has an open merge request to develop or something:
$ youtrack-thingy