Update hostsfile and add zerotier cookbook

cookbooks/zerotier/recipes/join_networks.rb

@@ -0,0 +1,23 @@
+#
+# Cookbook:: zerotier
+# Recipe:: join_networks
+#
+# Copyright:: 2017, ZeroTier, Inc., All Rights Reserved.
+
+include_recipe 'zerotier::ohai_plugin'
+
+node['zerotier']['public_autojoin'].each do |nwid|
+    zerotier_network nwid do
+        action :join
+    end
+end
+
+node['zerotier']['private_autojoin'].each do |network|
+    zerotier_network network['network_id'] do
+        only_if { network.key?("auth_token") }
+        action :join
+        auth_token network['auth_token']
+        central_url network.key?("central_url") ? network[:central_url] : "https://my.zerotier.com"
+        node_name node['fqdn']
+    end
+end