Sort visitors in alphabetical order.

lib/runosaari/registration.ex

@@ -133,6 +133,21 @@ defmodule Runosaari.Registration do
     Repo.all(Visitor)
   end
 
+  @doc """
+  Returns the alphabetically sorted list of visitors.
+
+  ## Examples
+
+      iex> list_visitors()
+      [%Visitor{}, ...]
+
+  """
+  def list_sorted_visitors do
+    Visitor
+    |> order_by(:lname)
+    |> Repo.all()
+  end
+
   @doc """
   Gets a single visitor.