Dear renkulab users,
the Renkulab 0.10.0 rollout went fine and you can now enjoy working with Renku again. 
In case you were not aware: there was a small outage this morning on renkulab.io, see the post-mortem, if you had open sessions there might be a chance that the unsaved work was kept in an auto-saved branch on your project. See this post for more details on how to potentially recover unsaved work.