talk duration is in minutes
schema update from 10 to 11

the legacy schema has been updated with the following:

    alter table talks add column teaser       text;
    alter table talks add column url_video1   text;
    alter table talks add column url_video2   text;
    alter table talks add column url_video3   text;
    alter table talks add column hide_details boolean DEFAULT false NOT NULL;
    alter table talks add column allow_record boolean DEFAULT true  NOT NULL;