A massive brawl at a hairdressing salon in Germany led to a major police response, including the deployment of a police helicopter on Thursday afternoon. A fist-fight broke out on the pavement outside the salon involving several people, and a 22-year-old man allegedly injured an 18-year-old with a knife, according to police. A large crowd of onlookers quickly gathered, leading police to call for additional assistance from neighbouring jurisdictions. The 22-year-old man who used the knife was detained by police, along with four other men between the ages of 18 and 21 who all tried to flee from …