add readable diff colors

vimrc

@@ -235,6 +235,12 @@ highlight YcmWarningSign ctermfg=Yellow
 highlight YcmErrorSection ctermfg=Red
 highlight YcmErrorsign ctermfg=Red
 
+"" diff colors
+highlight DiffAdd    cterm=bold ctermfg=10 ctermbg=17 gui=none guifg=bg guibg=Red
+highlight DiffDelete cterm=bold ctermfg=10 ctermbg=17 gui=none guifg=bg guibg=Red
+highlight DiffChange cterm=bold ctermfg=10 ctermbg=17 gui=none guifg=bg guibg=Red
+highlight DiffText   cterm=bold ctermfg=10 ctermbg=88 gui=none guifg=bg guibg=Red
+
 " place the vim-airline bar above the command line
 set laststatus=2