Trying to add myself fails, showing "Oops! Something uncool is breaking this app.". The POST request seems to be receiving 500 with the following request.

    -----------------------------74974701830891853922449739590
    Content-Disposition: form-data; name="1_username"
    
    qazxcvbnm
    -----------------------------74974701830891853922449739590
    Content-Disposition: form-data; name="1_location"
    
    Hong Kong Island, China
    -----------------------------74974701830891853922449739590
    Content-Disposition: form-data; name="0"
    
    ["$undefined","$K1"]
    -----------------------------74974701830891853922449739590--