Merge branch 'rubocop'

* rubocop:
  Additional fixes for rubocop 1.10.1
  Switch to rubocop 0.89.1

Switch to rubocop 0.89.1

This is the rubocop in new Debian stable

Customer Visible Plan Info

We moved some of the currently private things to be public, like currency, and
then included things like how much the monthly price is as well.

Customer always has a JID

Merge branch 'low-balance-auto-top-up'

* low-balance-auto-top-up:
  Some people have exactly 5 who don't need to be told
  On low balance, top-up or notify
  ExpiringLock helper

On low balance, top-up or notify

On start up, check for users with low balance and NOTIFY about them.  LISTEN for
such notifications and process by either sending a low-balance warning message
or else attempting an auto-top-up as configured.

Using NOTIFY/LISTEN because then we can NOTIFY after any INSERT that leaves the
balance too low (using a trigger).  Doing the sync on start-up in case we missed
a NOTIFY during any downtime.  Using the Redis lock to prevent spamming a
low-balance user in case of many restarts or if they have many small
transactions happen in one day.

When no plan, all plan attributes are nil

Merge branch 'create_customer_id'

* create_customer_id:
  Create customer_id if it does not exist before we start registration
  Break out CustomerPlan
  Inject BackendSgx per customer

Break out CustomerPlan

We had Plan and Customer but the relationship between the two lived
entirely in Customer, which was growing quite large. Break that
relationship out into its own concept and give it a name.