added nord colorscheme (#23)

* added nord colorscheme

* nord theme: only add the italics global if set

* Set colorscheme after globals

plugins/colorschemes/nord.nix

@@ -0,0 +1,49 @@
+{ pkgs, config, lib, ... }:
+with lib;
+let 
+  cfg = config.programs.nixvim.colorschemes.nord;
+in
+{
+  options = {
+    programs.nixvim.colorschemes.nord = {
+      enable = mkEnableOption "Enable nord";
+
+      contrast = mkEnableOption
+        "Make sidebars and popup menus like nvim-tree and telescope have a different background";
+
+      borders = mkEnableOption
+        "Enable the border between verticaly split windows visable";
+
+      disable_background = mkEnableOption
+        "Disable the setting of background color so that NeoVim can use your terminal background";
+
+      cursorline_transparent = mkEnableOption
+        "Set the cursorline transparent/visible";
+
+      enable_sidebar_background = mkEnableOption
+        "Re-enables the background of the sidebar if you disabled the background of everything";
+
+      italic = mkOption {
+        description = "enables/disables italics";
+        type = types.nullOr types.bool;
+        default = null;
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    programs.nixvim = {
+      colorscheme = "nord";
+      extraPlugins = [ pkgs.vimPlugins.nord-nvim ];
+
+      globals = {
+        nord_contrast = mkIf cfg.contrast 1;
+        nord_borders = mkIf cfg.borders 1;
+        nord_disable_background = mkIf cfg.disable_background 1;
+        nord_cursoline_transparent = mkIf cfg.cursorline_transparent 1;
+        nord_enable_sidebar_background = mkIf cfg.enable_sidebar_background 1;
+        nord_italic = mkIf (cfg.italic != null) cfg.italic;
+      };
+    };
+  };
+}

plugins/default.nix

@@ -5,6 +5,7 @@
 
     ./colorschemes/base16.nix
     ./colorschemes/gruvbox.nix
+    ./colorschemes/nord.nix
     ./colorschemes/one.nix
     ./colorschemes/onedark.nix
     ./colorschemes/tokyonight.nix