config/cachix/nix-community.nix

{
  nix = {
    settings = {
      substituters = [
        "https://nix-community.cachix.org"
      ];
      trusted-public-keys = [
        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
      ];
    };
  };
}