move packer_setup to plugins

lua/plugins/init.lua

@@ -1,3 +1,5 @@
+require('plugins.packer_setup')
+
 require('packer').startup(function()
 
   -- Packer can manage itself as an optional plugin
@@ -49,6 +51,7 @@ require('packer').startup(function()
   use { 'RRethy/vim-illuminate' } -- highlight all words same as the one under cursor
   use { 'vim-scripts/DrawIt' } -- ascii diagrams
   use { 'nathom/filetype.nvim' }
+
 end)
 
 require('plugins.cmp')

lua/plugins/packer_setup.lua

@@ -0,0 +1,9 @@
+-- Auto install packer.nvim if not exists
+local install_path = vim.fn.stdpath('data')..'/site/pack/packer/opt/packer.nvim'
+if vim.fn.empty(vim.fn.glob(install_path)) > 0 then
+  vim.api.nvim_command('!git clone https://github.com/wbthomason/packer.nvim '..install_path)
+end
+
+vim.cmd [[packadd packer.nvim]]
+-- Auto compile when there are changes in plugins.lua
+vim.cmd 'autocmd BufWritePost plugins.lua PackerCompile'