add fundraising API

lib/camp_api/grist/fundraising.ex

@@ -0,0 +1,14 @@
+defmodule CampApi.Grist.Fundraising do
+  @moduledoc false
+
+  alias CampApi.Grist
+
+  @gauge_doc "wWacvVWE9QtQ"
+  @gauge_table "Dons"
+
+  def get() do
+    {:ok, %{body: %{"records" => records}}} = Grist.get_records(@gauge_doc, @gauge_table)
+
+    records
+  end
+end