The bride wore white and carried a bouquet of plastic flowers, from Amazon. The aisle was from Amazon, too, and so were the fairy lights strung around the chuppah. The wedding party was small: only immediate family and the rabbi. Although rain had been forecast, the weather held, and when 23-year-old student Eliana Amrani, from Chicago, married her boyfriend, 22-year-old Elliot Birn, in her parents’ garden, the sun was shining. As is customary during Jewish weddings, the bride and groom prepared to smash a glass underfoot.