simplify JSON parsing
don't return an error if we can't write to memcache

This should only effect performance on subsequent requests and so the
error shouldn't be visible to the user.
only write 200 OK responses to the cache
whitespace
add a basic alert service
mv 'Welcome...' above the grid
don't require a celler user for the admin API

This resolves a bootstrapping issue since we need the admin API in
order to create users.
don't error when creating a non-existent user

This resolves a bootstrapping issue since we need to be able to create
users that, by definition, don't already exist.
add some bootstrapping notes to the README