[Triage] Allow changing SQLite journal mode (#145)

* Adds ability to configure journal mode for SQLite

* docs

* docs

config/test.exs

@@ -17,7 +17,6 @@ config :pinchflat, Oban, testing: :manual
 # Run `mix help test` for more information.
 config :pinchflat, Pinchflat.Repo,
   database: Path.expand("../priv/repo/pinchflat_test.db", Path.dirname(__ENV__.file)),
-  pool_size: 5,
   pool: Ecto.Adapters.SQL.Sandbox
 
 # We don't run a server during test. If one is required,