Add books.

lib/decentralised_book_index/books.ex

@@ -0,0 +1,8 @@
+defmodule DecentralisedBookIndex.Books do
+  use Ash.Domain,
+    otp_app: :decentralised_book_index
+
+  resources do
+    resource DecentralisedBookIndex.Books.Book
+  end
+end

lib/decentralised_book_index/books/book.ex

@@ -0,0 +1,30 @@
+defmodule DecentralisedBookIndex.Books.Book do
+  use Ash.Resource,
+    otp_app: :decentralised_book_index,
+    domain: DecentralisedBookIndex.Books
+
+  actions do
+    defaults [:read]
+  end
+
+  attributes do
+    uuid_primary_key :id
+
+    attribute :title, :string do
+      allow_nil? false
+      public? true
+    end
+
+    attribute :isbn, :string do
+      allow_nil? false
+      public? true
+    end
+
+    attribute :description, :string do
+      allow_nil? false
+      public? true
+    end
+
+    timestamps()
+  end
+end