Add rake, used for tests

Merge branch 'do-not-bill-unregistered'

* do-not-bill-unregistered:
  Query sgx-jmp for every expired user
  Show backtrace and bail out hard on panic

Query sgx-jmp for every expired user

If they have no assigned tel, do not bill them or notify them.

Show what tels are paid-up but not in dashboard

add sentry

Initial test suite and helpers

Notify customer when renewal fails due to low balance

This is done by sending from a configured JID to <tel>@cheogram.com in order to
have them receive a message from support.

Cronjob to check pending BTC transactions

When they become confirmed, insert them into the transactions table.
We can never double-insert because of the PRIMARY KEY on transaction_id, so the
script is always safe to run even if something ends up in redis twice.

Endpoint that pushes all unknown transactions into Redis

The intent is to use `electrum notify <address> <app>/electrum_noify?address=&customer_id=`

The app asks electrum for all transactions on that address, and then checks
which ones we *don't* already have recorded in the transactions table.  These
are pushed into Redis to be picked up by a to-be-written job that will write
them to the transactions table after 3 confirmations.

Initial commit