Fix link to Ceylon members

The link just pointed at the ceylon user page, which shows the repositories tab, not the users tab.
Fix link to Ceylon members again

Github just updated their organization profile pages [1], so the link has to be changed again. (Well, the old link currently redirects to the new one, but we should still use the “canonical” link directly.)

[1] https://github.com/blog/1763-better-organizations
Merge pull request #2 from lucaswerkmeister/patch-1

Fix link to Ceylon members