Implement document ownership and write control

Got everything together for basic ownership.
Documents have two new important fields:
    owner, the username of their creator
    protect, tracks whether writes are restricted to said owner
Put very basic interface for this in the sidebar.
We need an indication of whether the document is editable.
Probably the sidebar should disappear on the homepage, too.
Merge branch 'master' of github.com:croikle/octothorpe