Sofia Richie has got engaged. The 23-year-old model is set to marry music executive Elliot Grainge, 27, after a year of dating. Sharing a photo of the music executive’s proposal – in which Elliot got down on one knee amongst a bed of flower petals surrounded by candles – and another of her stunning engagement ring, Sofia wrote on Instagram: “Forever isn’t long enough @elliot (sic)” Her fiance shared a photo of them sharing a kiss and wrote: “She said yes [heart emojis] (sic)” It was claimed in November that Sofia and Elliot – who is the son of Universal Music Group CEO Lucian Grainge – had “ta…