fix(pastes): update schema with timestamps macro

Signed-off-by: Sphericalkat <amolele@gmail.com>

lib/ketbin/pastes/paste.ex

@@ -9,6 +9,8 @@ defmodule Ketbin.Pastes.Paste do
     field :content, :string
     field :is_url, :boolean, default: false
     field :belongs_to, :id
+
+    timestamps()
   end
 
   @doc false