Hi! Occasionally I'll see a notification pop up in the header bar, and when I click on it, instead of seeing the page listing the events (comments, likes), I get a lua error:

Error
./models/submission_comments.lua:68: attempt to index local 'submission' (a nil value)Traceback
stack traceback:
    ./models/submission_comments.lua:68: in function 'url_params'
    /home/leafo/.luarocks/share/lua/5.1/lapis/request.lua:31: in function 'url_for'
    ./views/notifications.lua:57: in function 'call'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:348: in function 'write'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:327: in function 'write_escaped'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:181: in function 'div'
    ./views/notifications.lua:33: in function 'call'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:348: in function 'write'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:327: in function 'write_escaped'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:181: in function 'clone'
    ...
    ./widgets/base.lua:37: in function 'clone'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:311: in function 'content'
    /home/leafo/.luarocks/share/lua/5.1/lapis/html.lua:538: in function 'thing'
    /home/leafo/.luarocks/share/lua/5.1/lapis/request.lua:89: in function 'write'
    /home/leafo/.luarocks/share/lua/5.1/lapis/request.lua:213: in function 'render'
    /home/leafo/.luarocks/share/lua/5.1/lapis/application.lua:136: in function </home/leafo/.luarocks/share/lua/5.1/lapis/application.lua:135>
    [C]: in function 'xpcall'
    /home/leafo/.luarocks/share/lua/5.1/lapis/application.lua:159: in function 'dispatch'
    /home/leafo/.luarocks/share/lua/5.1/lapis/nginx.lua:214: in function 'serve'
    content_by_lua(nginx.conf.compiled:41):2: in function <content_by_lua(nginx.conf.compiled:41):1>

Ditto... I think it's a site problem.