add nerdtree and nerdtree-git-plugin to vim

.gitmodules

@@ -31,3 +31,9 @@
 [submodule ".vim/bundle/vim-devicons"]
 	path = .vim/bundle/vim-devicons
 	url = https://github.com/ryanoasis/vim-devicons.git
+[submodule ".vim/bundle/nerdtree"]
+	path = .vim/bundle/nerdtree
+	url = https://github.com/scrooloose/nerdtree.git
+[submodule ".vim/bundle/nerdtree-git-plugin"]
+	path = .vim/bundle/nerdtree-git-plugin
+	url = https://github.com/Xuyuanp/nerdtree-git-plugin.git

.vimrc

@@ -306,6 +306,15 @@ let g:syntastic_auto_loc_list = 1
 let g:syntastic_check_on_open = 1
 let g:syntastic_check_on_wq = 0
 
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+"⋅=>⋅nerdtree settings
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+" Open a NERDTree automatically when no files were specified
+autocmd StdinReadPre * let s:std_in=1
+autocmd VimEnter * if argc() == 0 && !exists("s:std_in") | NERDTree | endif
+
+map <C-n> :NERDTreeToggle<CR>
+
 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
 " => Misc
 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
@@ -395,4 +404,4 @@ function! NumberToggle()
     set relativenumber
   endif
 endfunc
-nnoremap <C-n> :call NumberToggle()<cr>
+"nnoremap <C-n> :call NumberToggle()<cr>