running bin/nur update is too expensive

[milahu]

the readme says

How to add your own repository.

At the moment each URL must point to a git repository. By running bin/nur update the corresponding repos.json.lock is updated and the repository is tested. This will perform also an evaluation check, which must be passed for your repository. Commit the changed repos.json but NOT repos.json.lock

so i add my repo, run bin/nur update ... and my whole computer hangs ^^

lets ignore the facts that i should enable swap and use ulimit:
bin/nur update should not check all repos, but only the one repo (or few repos) that i want to add

the added repo can be found with git diff origin/HEAD
or diff <(curl https://raw.githubusercontent.com/nix-community/NUR/master/repos.json) repos.json

could be related to #186

[Mic92]

Right, when I started the project this was never an issue :) Now NUR grew quite a bit.

[Mic92]

But actually we start a new nix-env for every repo. So maybe its only a few repos that consumes a lot of ram.