[openstreetmap-website] Add welcome page (#338)

[vincentdephily]

Makes obvious and complete sense once somebody shows it to you. I approve the pre/post-login split.

---
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/openstreetmap-website/pull/338#issuecomment-21608079
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/rails-dev/attachments/20130726/f4de3639/attachment.html>