Add tree-sitter plugin

roles/neovim/files/lua/plugins.lua

@@ -12,6 +12,12 @@ return require('packer').startup(function(use)
   -- Nvim LSP
   use 'neovim/nvim-lspconfig'
 
+  -- Tree-sitter
+  use {
+    'nvim-treesitter/nvim-treesitter',
+    run = function() require('nvim-treesitter.install').update({ with_sync = true }) end,
+  }
+
   -- COLOR SCHEMES
   use 'morhetz/gruvbox'
   use 'sjl/badwolf'