Switch vim colorscheme to gruvbox (#23)

.config/nvim/colors/seoul256-light.vim

@@ -0,0 +1,76 @@
+" "  _____             _ ___ ___ ___            "
+" " |   __|___ ___ _ _| |_  |  _|  _|           "
+" " |__   | -_| . | | | |  _|_  | . |           "
+" " |_____|___|___|___|_|___|___|___|-light.vim "
+"
+" " Low-contrast light Vim color scheme using Seoul Colors "
+"
+" File:         seoul256-light.vim
+" URL:          github.com/junegunn/seoul256.vim
+" Author:       Junegunn Choi (junegunn.c@gmail.com)
+" License:      MIT
+"
+" Copyright (c) 2017 Junegunn Choi
+"
+" MIT License
+"
+" Permission is hereby granted, free of charge, to any person obtaining
+" a copy of this software and associated documentation files (the
+" "Software"), to deal in the Software without restriction, including
+" without limitation the rights to use, copy, modify, merge, publish,
+" distribute, sublicense, and/or sell copies of the Software, and to
+" permit persons to whom the Software is furnished to do so, subject to
+" the following conditions:
+"
+" The above copyright notice and this permission notice shall be
+" included in all copies or substantial portions of the Software.
+"
+" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+" EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+" NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+" LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+" OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+" WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+let s:master    = expand('<sfile>:p:h').'/seoul256.vim'
+let s:custom_bg = get(g:, 'seoul256_light_background', get(g:, 'seoul256_background', 253))
+let s:light     = s:custom_bg >= 252 && s:custom_bg <= 256
+let s:var_found = exists('g:seoul256_background')
+let s:light_var_found = exists('g:seoul256_light_background')
+
+if filereadable(s:master)
+  try
+    " Backup current g:seoul256_background
+    if s:var_found
+      let s:backup = g:seoul256_background
+    endif
+
+    " Invalid range. Force the default light version.
+    if !s:light && s:var_found
+      unlet g:seoul256_background
+    endif
+
+    " g:seoul256_light_background is found, use it
+    if s:light && s:light_var_found
+      let g:seoul256_background = s:custom_bg
+    endif
+
+    if get(g:, 'colors_name', '') == 'seoul256-light' && &background == 'dark'
+      set background=dark
+    else
+      set background=light
+    endif
+    let g:colors_name = 'seoul256'
+    execute 'silent source' fnameescape(s:master)
+    let g:colors_name = &background == 'dark' ? 'seoul256' : 'seoul256-light'
+  finally
+    " Revert g:seoul256_background
+    if s:var_found
+      let g:seoul256_background = s:backup
+    endif
+  endtry
+else
+  echom 'seoul256.vim not found'
+endif
+