make clean: Delete darcs-repo
Use hydra-init / hydra-create-user in the tests
Make /login give a proper JSON response again
Test whether incorrect passwords are rejected
hydra-module.nix: Don't create an admin user

It's the user's job to create users with the appropriate roles.
hydra-module.nix: Remove the useWAL option

This is not a Hydra option but a Nix option so it shouldn't be here.
hydra-module.nix: Give types to options

Also, rename the "service.hydra.hydra" option to
"service.hydra.package" to be consistent with NixOS option naming
conventions.
hydra-module.nix: Don't use a password

If PostgreSQL is running on the same system, then the "hydra" user can
can connect without a password (via Unix domain socket
authentication), so no need to set up a password.  If PostgreSQL is on
another machine, then creating a user/database won't work anyway.
hydra-module.nix: Make services require hydra-init
hydra-module.nix: Use -p instead of HYDRA_PORT
hydra-module.nix: Fix setting the logo
hydra-module.nix: Use startAt
hydra-module.nix: More paranoid permissions on the data directory
hydra-module.nix: Export the HYDRA_* environment variables

This is useful if you want to run hydra-* commands manually.
Use hydra-module.nix in the tests