Switch to sqlite (#22)

* Updated project to use sqlite

* Edited migrations directly because I fear no man

* Updated search functions and tests to work with sqlite

* Updated build tools to remove postgres

lib/pinchflat/repo.ex

@@ -1,7 +1,7 @@
 defmodule Pinchflat.Repo do
   use Ecto.Repo,
     otp_app: :pinchflat,
-    adapter: Ecto.Adapters.Postgres
+    adapter: Ecto.Adapters.SQLite3
 
   @doc """
   It's not immediately obvious if an Oban job qualifies as unique, so this method