add go plugin and change default color

.vimrc

@@ -17,6 +17,7 @@ Plug 'vim-airline/vim-airline'
 Plug 'tpope/vim-fugitive'
 Plug 'xuyuanp/nerdtree-git-plugin'
 Plug 'flazz/vim-colorschemes'
+Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }
 
 call plug#end()
 
@@ -50,4 +51,4 @@ set expandtab
 set wildmode=longest,list,full
 set wildmenu
 
-colorscheme chalkboard
+colorscheme slate