"install the colorschemes you want
call plug#begin('~/.vim/plugged')
Plug 'ErichDonGubler/vim-sublime-monokai' "colorscheme
Plug 'NLKNguyen/papercolor-theme'
call plug#end()

" set all the colorscheme options
let g:sublimemonokai_term_italic = 1

" set the default colorscheme
colorscheme sublimemonokai

" set the colorscheme you want - this can be moved to the function below - but for me this way is more flexible,
" I can change the colorscheme by calling :Dark/:light
" You may want to set the background variable - sublimemonokai sets it programmatically to dark
command DarkTheme colorscheme sublimemonokai
command LightTheme set background=light | colorscheme PaperColor

function ToggleColorTheme()
  if &background == "dark"
    LightTheme
  else
    DarkTheme
  endif
endfunction

" call the function on button press
nnoremap <leader>c :call ToggleColorTheme()<CR>