vim: add vim-tmux-focus-events; set autoread

vimrc

@@ -37,6 +37,7 @@ call plug#begin('~/.vim/plugged')
     Plug 'wesQ3/vim-windowswap'
     Plug 'majutsushi/tagbar'
     Plug 'tpope/vim-obsession'
+    Plug 'tmux-plugins/vim-tmux-focus-events'
 
     if version >= 800
         Plug 'neoclide/coc.nvim', {'branch': 'release'}
@@ -45,6 +46,9 @@ call plug#begin('~/.vim/plugged')
     Plug 'dense-analysis/ale'
     Plug 'tpope/vim-commentary'
 
+    Plug 'vim-airline/vim-airline'
+    Plug 'vim-airline/vim-airline-themes'
+
     Plug 'posva/vim-vue'
     Plug 'ap/vim-css-color'
     Plug 'pangloss/vim-javascript'
@@ -76,8 +80,13 @@ map =j :%!jq<CR>
 set backupdir=/tmp//,.
 set directory=/tmp//,.
 
+" Enable visible line numbers
 set number
 
+" When we return to Vim, or re-enter a buffer, check if it's been modified.
+set autoread
+au FocusGained,BufEnter * :checktime
+
 " Make the current word upper-case; useful for constants.
 nnoremap <leader>wu  viwU
 nnoremap <leader>wl  viwu