disable autostart/autostop

I don't know why, but Fly didn't restart the machine even when requests
were coming in, so that doesn't actually seem like it's going to work
for us.

fly.toml

@@ -17,9 +17,8 @@ console_command = "/rails/bin/rails console"
 [http_service]
   internal_port = 3000
   force_https = true
-  auto_stop_machines = true
-  auto_start_machines = true
-  min_machines_running = 0
+  auto_stop_machines = false
+  auto_start_machines = false
   processes = ["app"]
 
 [[vm]]