Moved env to shell

shell-modules/env.nix

@@ -1,11 +0,0 @@
-{ lib, ... }:
-
-with lib;
-{
-  options = {
-    env = mkOption {
-      type = types.attrsOf types.str;
-      default = [ ];
-    };
-  };
-}

shell-modules/shell.nix

@@ -0,0 +1,17 @@
+{ lib, ... }:
+
+with lib;
+{
+  options = {
+    env = mkOption {
+      type = types.attrsOf types.str;
+      default = [ ];
+    };
+
+    packages = mkOption {
+      type = types.listOf types.package;
+      default = [ ];
+      description = "Packages to install";
+    };
+  };
+}