chore: working on code smells

lib/bds/posts/link.ex

@@ -7,6 +7,16 @@ defmodule BDS.Posts.Link do
   @primary_key {:id, :string, autogenerate: false}
   @foreign_key_type :string
 
+  @type t :: %__MODULE__{
+          id: String.t() | nil,
+          source_post_id: String.t() | nil,
+          target_post_id: String.t() | nil,
+          source_post: term(),
+          target_post: term(),
+          link_text: String.t() | nil,
+          created_at: integer() | nil
+        }
+
   schema "post_links" do
     belongs_to :source_post, BDS.Posts.Post, foreign_key: :source_post_id, references: :id, type: :string
     belongs_to :target_post, BDS.Posts.Post, foreign_key: :target_post_id, references: :id, type: :string
@@ -15,6 +25,7 @@ defmodule BDS.Posts.Link do
     field :created_at, :integer
   end
 
+  @spec changeset(t() | Ecto.Changeset.t(), map()) :: Ecto.Changeset.t()
   def changeset(link, attrs) do
     link
     |> cast(attrs, [:id, :source_post_id, :target_post_id, :link_text, :created_at])