The foreign-donated [Torah] scroll was placed in a room of the partially renovated synagogue on the edge of the site which the Romans attacked from a sloping ramp in 73 AD
The Romans captured the fortress only after its 900 defenders committed mass suicide and Masada is now a major site of pilgrimage for Jews around the world.
The religious emergency volunteer organisation Zaka, which organised the event, explained an active synagogue on the site was needed for the thousands of Jewish visitors who until now needed to bring a scroll to pray.
This article makes it sound as though the ruin of the synagogue is being rebuilt for modern use, but it doesn't say by whom or how. This worries me: the ruin is itself an archaeological and historical treasure. Any new buildings on the site should not interfere with the architechture already there. I'd like to know more about this.
UPDATE (30 May): More here.