Add grafana

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

packages/docker/prometheus/default.nix

@@ -0,0 +1,18 @@
+{ pkgs, ... }:
+pkgs.dockerTools.buildImage {
+  name = "prometheus";
+  fromImage = import ../base { inherit pkgs; };
+
+  copyToRoot = pkgs.buildEnv {
+    name = "root";
+    paths = with pkgs; [ prometheus ];
+    pathsToLink = [ "/bin" ];
+  };
+
+  config = {
+    Entrypoint = [ "/bin/prometheus" ];
+    ExposedPorts = {
+      "9090/tcp" = { };
+    };
+  };
+}