Add some documentation.

playbooks/roles/edx_vpc/tasks/main.yml

@@ -12,14 +12,19 @@
 # Tasks for role edx_vpc
 # 
 # Overview:
+# This role creates an opinionated vpc for containing cluster of edx services.
 # 
-#
-# Dependencies:
-#
+# It currently assumes that we will be multi-az, with a single NAT, and all
+# traffic going over that NAT.  A public subnet, and both public and private
+# route tables are created by default that can be used by new services in this
+# vpc.  The public subnet should house ELBs and any newly created private subnets
+# can use the existing private route table to be able to reach the internet from
+# private machines.
 # 
-# Example play:
 #
+# Example play:
 #
+# ansible-playbook -c local -i localhost, edx_vpc.yml -e@/Users/feanil/src/edx-secure/cloud_migrations/vpcs/test.yml
 
 # DO NOT use the subnet or route table sections of this command.
 # They will delete any subnets or rts not defined here which is