The so-called Islamic State group has claimed responsibility for a knife attack in the German city of Solingen on Friday evening that killed three people and wounded eight others. The group said in a statement published on its Amaq news site that the attacker is a ‘soldier of the Islamic State’ who targeted Christians and carried out the attack ‘to avenge Muslims in Palestine and everywhere.’ That announcement comes after German police told the dpa news agency that a second person had been arrested in connection with the stabbings. Saturday’s arrest happened in a refugee centre in Solingen. Ea…