Add nvim and phpactor plugin

programs/nvim.nix

@@ -0,0 +1,12 @@
+{ pkgs, ... }:
+
+{
+  programs.neovim = {
+    enable = true;
+
+    # Plugins installed via Nix
+    plugins = with pkgs.vimPlugins; [
+       phpactor
+    ];
+  };
+}