make nix ready

backend/default.nix

@@ -1,37 +1,4 @@
-let
-  config = {
-    packageOverrides = pkgs: rec {
-      haskellPackages = pkgs.haskellPackages.override {
-        overrides = haskellPackagesNew: haskellPackagesOld: rec {
-          jitsi-rooms =
-            haskellPackagesNew.callPackage ./converted.nix { };
-        };
-      };
-    };
-  };
-  pkgs = import <nixpkgs> { inherit config; };
+{ pkgs ? import <nixpkgs> { } }:
 
 
-in
-pkgs.dockerTools.buildImage {
-  name = "jitsi-rooms";
-  tag = "latest";
-  copyToRoot = pkgs.buildEnv {
-    name = "image-root";
-    paths = [
-      # pkgs.bash
-      # pkgs.coreutils
-    ];
-    pathsToLink = [ "/bin" ];
-  };
-  config = {
-    Cmd = [ "${pkgs.haskellPackages.jitsi-rooms}/bin/jitsi-rooms-exe" ];
-    ExposedPorts = {
-      "9160/tcp" = { };
-      "8081/tcp" = { };
-    };
-    Env = [
-      "LANG=en_US.UTF-8"
-    ];
-  };
-}
+pkgs.haskellPackages.callPackage ./converted.nix { }

backend/docker.nix

@@ -0,0 +1,37 @@
+let
+  config = {
+    packageOverrides = pkgs: rec {
+      haskellPackages = pkgs.haskellPackages.override {
+        overrides = haskellPackagesNew: haskellPackagesOld: rec {
+          jitsi-rooms =
+            haskellPackagesNew.callPackage ./converted.nix { };
+        };
+      };
+    };
+  };
+  pkgs = import <nixpkgs> { inherit config; };
+
+
+in
+pkgs.dockerTools.buildImage {
+  name = "jitsi-rooms";
+  tag = "latest";
+  copyToRoot = pkgs.buildEnv {
+    name = "image-root";
+    paths = [
+      # pkgs.bash
+      # pkgs.coreutils
+    ];
+    pathsToLink = [ "/bin" ];
+  };
+  config = {
+    Cmd = [ "${pkgs.haskellPackages.jitsi-rooms}/bin/jitsi-rooms-exe" ];
+    ExposedPorts = {
+      "9160/tcp" = { };
+      "8081/tcp" = { };
+    };
+    Env = [
+      "LANG=en_US.UTF-8"
+    ];
+  };
+}

backend/src/Types/WebSocketMessages/WebSocketMessages.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE GADTs #-}
 
 module Types.WebSocketMessages.WebSocketMessages
   ( WebSocketMessage (..),