Switch vim colorscheme to gruvbox (#23)

.config/nvim/colors/default.vim

@@ -0,0 +1,23 @@
+" Vim color file
+" Maintainer:	Bram Moolenaar <Bram@vim.org>
+" Last Change:	2001 Jul 23
+
+" This is the default color scheme.  It doesn't define the Normal
+" highlighting, it uses whatever the colors used to be.
+
+" Set 'background' back to the default.  The value can't always be estimated
+" and is then guessed.
+hi clear Normal
+set bg&
+
+" Remove all existing highlighting and set the defaults.
+hi clear
+
+" Load the syntax highlighting defaults, if it's enabled.
+if exists("syntax_on")
+  syntax reset
+endif
+
+let colors_name = "default"
+
+" vim: sw=2