My fixed snippet for generation of tag list using PhoenixHTML

tag_link_list.ex

  defp tag_to_link(conn, tag) do
      {:safe, body} = link to: Router.Helpers.tag_path(conn, :show, tag.id) do
      	   tag.name
      end
      body
  end

  @doc """
  Produces a comma-separated list of links to tag pages for tags
  in a post (commas are TBD)

  ## Example
  Given a post with two tags, Foo (1) and Bar (2), in a template this...

     <%= tag_link_list(@conn, @post) %>

  should produce this...

     <div class="taglist"><a href="/tag/1">Foo</a><a href="/tag/2">Bar</a></div>
 
  Now that I'm not using tag function it works, though is ugly
  """
  def tag_link_list(conn, post) do
     tags = Repo.all( from t in Tagging, where: t.post_id == ^post.id,  preload: [:tag]) |> Enum.map(&(&1.tag))
     links = ["<div>",Enum.map(tags, fn (t) -> tag_to_link(conn, t) end), "</div>"]
     {:safe, links}    
  end