Chelsea have completed the signing of Ukraine forward Mykhailo Mudryk from Shakhtar Donetsk in a deal worth up to £89m.The 22-year-old has agreed an eight-and-a-half-year deal for 70m euros (£62m), plus a further 30m euros (£27m) in bonuses.Arsenal also wanted Mudryk, who scored seven goals in 12 league appearances for Shakhtar this season.