timezone fix

app/views/calendars/show.ics.erb

@@ -2,7 +2,22 @@ BEGIN:VCALENDAR
 VERSION:2.0
 PRODID:http://www.example.com/calendarapplication/
 METHOD:PUBLISH
-X-WR-TIMEZONE:Vienna
+X-WR-TIMEZONE:Europe/Vienna
+BEGIN:VTIMEZONE
+TZID:Europe/Vienna
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+DTSTART:19810329T020000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
+TZNAME:MESZ
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+DTSTART:19961027T030000
+RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
+TZNAME:MEZ
+END:STANDARD
+END:VTIMEZONE
 <% @calendar.calentries.each do |entry| %>
 <%= render entry %>
 <% end %>