Fix participant cleanup logic

public/vroom.pl

@@ -366,8 +366,9 @@ helper has_joined => sub {
 helper delete_participants => sub {
   my $self = shift;
   $self->app->log->debug('Removing inactive participants from the database');
+  my $timeout = time()-600;
   my $sth = eval {
-    $self->db->prepare("DELETE FROM `participants` WHERE (`activity_timestamp` < 600 OR `activity_timestamp` IS NULL);")
+    $self->db->prepare("DELETE FROM `participants` WHERE (`activity_timestamp` < $timeout OR `activity_timestamp` IS NULL);")
   } || return undef;
   $sth->execute() || return undef;
   return 1;