Switch vim colorscheme to gruvbox (#23)

.config/nvim/colors/zellner.vim

@@ -0,0 +1,54 @@
+" local syntax file - set colors on a per-machine basis:
+" vim: tw=0 ts=4 sw=4
+" Vim color file
+" Maintainer:	Ron Aaron <ron@mossbayeng.com>
+" Last Change:	2001 July 13
+
+set background=light
+hi clear
+if exists("syntax_on")
+  syntax reset
+endif
+let g:colors_name = "zellner"
+
+hi Comment term=bold ctermfg=Red guifg=Red
+hi Normal guifg=black guibg=white
+hi Constant term=underline ctermfg=Magenta guifg=Magenta
+hi Special term=bold ctermfg=Magenta guifg=Magenta
+hi Identifier term=underline ctermfg=Blue guifg=Blue
+hi Statement term=bold ctermfg=DarkRed gui=NONE guifg=Brown
+hi PreProc term=underline ctermfg=Magenta guifg=Purple
+hi Type term=underline ctermfg=Blue gui=NONE guifg=Blue
+hi Visual term=reverse ctermfg=Yellow ctermbg=Red gui=NONE guifg=Black guibg=Yellow
+hi Search term=reverse ctermfg=Black ctermbg=Cyan gui=NONE guifg=Black guibg=Cyan
+hi Tag term=bold ctermfg=DarkGreen guifg=DarkGreen
+hi Error term=reverse ctermfg=15 ctermbg=9 guibg=Red guifg=White
+hi Todo term=standout ctermbg=Yellow ctermfg=Black guifg=Blue guibg=Yellow
+hi  StatusLine term=bold,reverse cterm=NONE ctermfg=Yellow ctermbg=DarkGray gui=NONE guifg=Yellow guibg=DarkGray
+hi! link MoreMsg Comment
+hi! link ErrorMsg Visual
+hi! link WarningMsg ErrorMsg
+hi! link Question Comment
+hi link String	Constant
+hi link Character	Constant
+hi link Number	Constant
+hi link Boolean	Constant
+hi link Float		Number
+hi link Function	Identifier
+hi link Conditional	Statement
+hi link Repeat	Statement
+hi link Label		Statement
+hi link Operator	Statement
+hi link Keyword	Statement
+hi link Exception	Statement
+hi link Include	PreProc
+hi link Define	PreProc
+hi link Macro		PreProc
+hi link PreCondit	PreProc
+hi link StorageClass	Type
+hi link Structure	Type
+hi link Typedef	Type
+hi link SpecialChar	Special
+hi link Delimiter	Special
+hi link SpecialComment Special
+hi link Debug		Special