libs:
- iron_slog
- testing: keep it simple: iron-test
    => if that is annoying, shiny? mockers if needed.
- sentry
- start with dotenv+clap, then config-rs?
- cadence (emits statsd)
- frank_jwt and JWT for (simple?) auth

metrics:
- best would be something with a configurable back-end, like 'log' for logging,
  but supporing tags/labels. the prometheus model probably makes most sense by
  default (really nice to be able to grab metrics with 'curl'/browser for
  individual instances), but statsd seems to be what we run in production. not
  spewing out lots of UDP by default seems like a good idea.
- dipstick: has all the good features, and popular, but code quality has smells
  ("a32dlkjhw"-style commit messages), and API doesn't seem very clean. Also
  prometheus stuff not actually implemented
- cadence: seems stable, somewhat popular, clean API. statsd-only for now, but
  has custom backends that could be hooked on to. *super* few dependencies,
  nice.
- tic: many deps; doesn't seem stable or under development
- rust-prometheus: developed by pingcap (large company). has push and pull
  features. medum-sized deps; has feature flags

A nice feature of a statsd solution is that collectd is usually running
locally (on linux dev, or in production), and metrics can be sent there by
default, like journald for logging.

Seems like a decision between cadence (statsd) and rust-prometheus.

similar:
- https://github.com/DavidBM/templic-backend
- https://github.com/alexanderbanks/rust-api
- https://mgattozzi.com/diesel-powered-rocket
- https://www.reddit.com/r/rust/comments/8j1xbs/new_to_rust_and_gitlab_ci/
- https://crate-ci.github.io/

"cool tools":
- cargo-watch