exclude build directory in vagrant rsync

Vagrantfile

@@ -6,7 +6,7 @@ vagrantfile = File.join("#{Dir.home}", '.VagrantFile')
 load File.expand_path(vagrantfile) if File.exists?(vagrantfile)
 
 Vagrant.configure('2') do |config|
-  config.vm.synced_folder "./", "/vagrant", type: "rsync", rsync__exclude: [ '.vagrant', '.git' ]
+  config.vm.synced_folder "./", "/vagrant", type: "rsync", rsync__exclude: [ '.vagrant', '.git', 'build' ]
   config.ssh.shell="/bin/sh"
 
   config.vm.provider :libvirt do |libvirt|