Server-rendered rel=me links

Currently /:username and /users/:username just return a script tag and some meta information. The page is then rendered by js.

This prevents external rel=mes to validate, as there's no linkback unless the page is fully rendered (and no checker does this).

Would it be possible to add a rel=me link to the server-generated html in addition to the other metadata? I see something similar is already done for twitter descriptions.

To Do:

• Put the user bio into the metadata (see router.ex / redirector, where the metadata is injected)

Related to #810 (closed)