Kendrick Lamar and Dr. Dre have paid it forward to their alma mater by showing up for students at the Compton, California high school they both attended. On Thursday (May 7), the two hip-hop greats attended a groundbreaking ceremony at Centennial High School that marked the construction of a new school building that will house more than 1,000 students. Others who joined the event included Will.i.am , a Los Angeles native, and U.S. Rep Maxine Waters. In a speech, Dre joked that he was enrolled at Centennial and attended "sometimes." He went to the school for his freshman year in 1979 before transferring and eventually dropping out. The co-founder of Death Row Records also recognized his hometown for its part in his legacy. "Today isn’t just about a new building, it’s about a new promise kept to the city that made me, point blank period,” he said. School board members and local leaders thanked the artists for their contributions to entertainment and the local community.…