message: Make it clear what's happening when `cargo run` hangs for 10 seconds
  I kept hitting this locally and got annoyed.
diff: use crate::metrics::Metrics;
  use crate::Config;
  +use log::debug;
  use postgres::{Client, NoTls};
  use r2d2_postgres::PostgresConnectionManager;
  use std::sync::Arc;
  @@ -20,6 +21,9 @@ pub struct Pool {
  impl Pool {
  pub fn new(config: &Config, metrics: Arc<Metrics>) -> Result<Pool, PoolError> {
  + debug!(
  + "creating database pool (if this hangs, consider running `docker-compose up -d db s3`)"
  + );
  Self::new_inner(config, metrics, DEFAULT_SCHEMA)
  }
  