Add scaling & test scaling

[Akeboshiwind]

We don't expect this to have a huge amount of users (especially at the beginning), so no real need to scale.
But if we explode on HN or something we could end up with a spike of users.

So we should scale the number of instances when that happens.

We should also test that the scaling works.

[Akeboshiwind]

https://github.com/wg/wrk

[mpisanko]

lambda handles that for us, doesn't it?
default is 1000 concurrent functions across all regions - think we should be fine?

[Akeboshiwind]

You’re right, I think this was before we were running on the lambda