Add dev shells

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

flake.nix

@@ -45,6 +45,10 @@
       url = "github:nix-community/NUR";
     };
 
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+    };
+
     ags = {
       url = "github:Aylur/ags";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -68,7 +72,19 @@
           modules = [ ./hosts/eirene ];
         };
       };
+    }
+    // inputs.flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells = {
+          nix = import ./hosts/common/system/shells/nix { inherit pkgs; };
+          python = import ./hosts/common/system/shells/python { inherit pkgs; };
+        };
 
-      formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt-rfc-style;
-    };
+        formatter = pkgs.nixfmt-rfc-style;
+      }
+    );
 }