Refactor modules into contexts (#78)

* [WIP] break out a few contexts, start refactoring fast index modules

* [WIP] more contexts, this time around slow indexing and downloads

* [WIP] got all tests passing

* [WIP] Added moduledocs

* Built a genserver to rename old jobs on boot

* Added a module naming check; moved things around

* Fixed specs

lib/pinchflat/boot/post_job_startup_tasks.ex

@@ -0,0 +1,44 @@
+defmodule Pinchflat.Boot.PostJobStartupTasks do
+  @moduledoc """
+  This module is responsible for running startup tasks on app boot
+  AFTER the job runner has initiallized.
+
+  It's a GenServer because that plays REALLY nicely with the existing
+  Phoenix supervision tree.
+  """
+
+  # restart: :temporary means that this process will never be restarted (ie: will run once and then die)
+  use GenServer, restart: :temporary
+  import Ecto.Query, warn: false
+
+  alias Pinchflat.Repo
+  alias Pinchflat.Boot.DataBackfillWorker
+
+  def start_link(opts \\ []) do
+    GenServer.start_link(__MODULE__, %{}, opts)
+  end
+
+  @doc """
+  Runs application startup tasks.
+
+  Any code defined here will run every time the application starts. You must
+  make sure that the code is idempotent and safe to run multiple times.
+
+  This is a good place to set up default settings, create initial records, stuff like that.
+  Should be fast - anything with the potential to be slow should be kicked off as a job instead.
+  """
+  @impl true
+  def init(state) do
+    enqueue_backfill_worker()
+
+    {:ok, state}
+  end
+
+  defp enqueue_backfill_worker do
+    DataBackfillWorker.cancel_pending_backfill_jobs()
+
+    %{}
+    |> DataBackfillWorker.new()
+    |> Repo.insert_unique_job()
+  end
+end