feat: more completeness of spec and start at embedding

lib/bds/embeddings/dismissed_duplicate_pair.ex

@@ -0,0 +1,24 @@
+defmodule BDS.Embeddings.DismissedDuplicatePair do
+  @moduledoc false
+
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @primary_key {:id, :string, autogenerate: false}
+  @foreign_key_type :string
+
+  schema "dismissed_duplicate_pairs" do
+    belongs_to :project, BDS.Projects.Project, type: :string
+    field :post_id_a, :string
+    field :post_id_b, :string
+    field :dismissed_at, :integer
+  end
+
+  def changeset(pair, attrs) do
+    pair
+    |> cast(attrs, [:id, :project_id, :post_id_a, :post_id_b, :dismissed_at])
+    |> validate_required([:id, :project_id, :post_id_a, :post_id_b, :dismissed_at])
+    |> foreign_key_constraint(:project_id)
+    |> unique_constraint(:post_id_a, name: :dismissed_pairs_idx)
+  end
+end