Save user database periodically to avoid data loss
Save user database periodically to avoid data loss

Periodically sync mudb content to usrdb so we don't loss user created
phrase and freq when crash.

Currently the interval is set to 16 input ops or 30 seconds between
saving.

kaio/ibus-table,mike-fabian/ibus-table,kaio/ibus-table,mike-fabian/ibus-table