Add application and tile servers to private subnets
Add a new cache parameter group that explicitly sets appendonly
Switch ElastiCache instance types to cache.m1.small

Smallest instance type that supports Redis' appendonly=yes
Add egress rules to bastion security group

- SSH
- Redis
- PostgreSQL
Allow bastion to hit the app and tile servers over HTTP
Lock down SSH into app and tile server to the bastion
Stop using ELB FQDNs; instead use ELB name
Tags propagated by ASG shouldn't include asg prefix