Ensure that database timezone matches IRIS time zone

All travelynx and IRIS timestamps are Europe/Berlin. And the DateTime objects
know that they are Europe/Berlin. However, when inserting into a timestamp with
time zone column, Mojo::Pg or one of the backend DBI/DBD libraries does not
respect the time zone. So, UTC+1 or UTC+2 timestamps are treated as UTC+0,
resulting in major mayhem.

lib/Travelynx.pm

@@ -369,6 +369,15 @@ sub startup {
 			state $pg
 			  = Mojo::Pg->new("postgresql://${user}\@${host}:${port}/${dbname}")
 			  ->password($pw);
+
+			$pg->on(
+				connection => sub {
+					my ( $pg, $dbh ) = @_;
+					$dbh->do("set time zone 'Europe/Berlin'");
+				}
+			);
+
+			return $pg;
 		}
 	);