Add postgres replica bootstrap example

README.md

@@ -38,6 +38,10 @@ Clone this repository, `cd` into it, and run:
 
     knife zero bootstrap ubuntu@zerotier-ip-address -x ubuntu --sudo --run-list "role[base],role[kvm_guest]" --secret-file .chef/encrypted_data_bag_secret
 
+### Bootstrap a new VM with environment and role/app (postgres replica as example)
+
+    knife zero bootstrap ubuntu@10.1.1.134 -x ubuntu --sudo --environment production --run-list "role[base],role[kvm_guest],role[postgresql_replica]" --secret-file .chef/encrypted_data_bag_secret
+
 ### Run Chef Zero on a host server
 
     knife zero converge -p2222 name:server-name.kosmos.org