This runs a migration on the primary node by doing the following:
1. Disables traffic to load balancer
2. Grab the domain and desired secondary node count from `terraform.tfvars`
3. Stops all primary and secondary nodes
4. Waits for health check to fail
5. Redeploys the primary node, causing the migration to run
6. Redeploys the secondary nodes
7. Waits for health check to succeed
8. Re-enables traffic to load balancer
On running the script on my personal setup, the migration script took 15 minutes