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

priv/repo/migrations/20240125165519_add_index_frequency_to_channels.exs

@@ -1,8 +1,8 @@
-defmodule Pinchflat.Repo.Migrations.AddIndexFrequencyToChannels do
+defmodule Pinchflat.Repo.Migrations.AddIndexFrequencyToSources do
   use Ecto.Migration
 
   def change do
-    alter table(:channels) do
+    alter table(:sources) do
       add :index_frequency_minutes, :integer, default: 60 * 24, null: false
     end
   end