add new plugin, fern

.gitmodules

@@ -28,3 +28,6 @@
 [submodule "bundle/vim-transparent"]
 	path = bundle/vim-transparent
 	url = https://github.com/tribela/vim-transparent
+[submodule "bundle/vim-fern"]
+	path = bundle/vim-fern
+	url = https://github.com/lambdalisue/vim-fern

.vimrc

@@ -100,3 +100,9 @@ let g:UltiSnipsExpandTrigger="<tab>"
 let g:UltiSnipsJumpForwardTrigger="<tab>"
 let g:UltiSnipsJumpBackwardTrigger="<S-tab>"
 let g:UltiSnipsEditSplit="vertical"
+
+
+"
+" ---- plugin: Fern
+"
+nmap <Space>f :Fern . -drawer -reveal=%<CR>