record initial source change on upload

lib/philomena/images.ex

@@ -67,6 +67,11 @@ defmodule Philomena.Images do
       |> Image.cache_changeset()
       |> repo.update()
     end)
+    |> Multi.run(:source_change, fn repo, %{image: image} ->
+      %SourceChange{image_id: image.id, initial: true}
+      |> SourceChange.creation_changeset(attrs, attribution)
+      |> repo.insert()
+    end)
     |> Multi.run(:added_tag_count, fn repo, %{image: image} ->
       tag_ids = image.added_tags |> Enum.map(& &1.id)
       tags = Tag |> where([t], t.id in ^tag_ids)

lib/philomena_web/templates/image/_source.html.slime

@@ -35,7 +35,7 @@
       - else
         em> not provided yet
 
-      = if @source_change_count > 0 do
+      = if @source_change_count > 1 do
         a.button.button--link.button--separate-left href=Routes.image_source_change_path(@conn, :index, @image) title="Source history"
           i.fa.fa-history>
           | History (