Source title regex filtering (#98)

* Added a basic/advanced mode to source form

* Added regex field and UI to source form

* Implemented title regex filtering

priv/repo/migrations/20240320153902_add_title_regex_to_source.exs

@@ -0,0 +1,9 @@
+defmodule Pinchflat.Repo.Migrations.AddTitleRegexToSource do
+  use Ecto.Migration
+
+  def change do
+    alter table(:sources) do
+      add :title_filter_regex, :string
+    end
+  end
+end