added vim-plug and plugins auto install scripts

.vimrc

@@ -1,3 +1,14 @@
+" Install vim-plug if not found
+if empty(glob('~/.vim/autoload/plug.vim'))
+  silent !curl -fLo ~/.vim/autoload/plug.vim --create-dirs
+    \ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim
+endif
+
+" Run PlugInstall if there are missing plugins
+autocmd VimEnter * if len(filter(values(g:plugs), '!isdirectory(v:val.dir)'))
+  \| PlugInstall --sync | source $MYVIMRC
+\| endif
+
 call plug#begin('~/.vim/plugged')
 
 " install with vim-plug