Tanner Martin, 30, was diagnosed with colorectal cancer when he was 25
                                
                                
                                    (Newser) -
                                    Tanner Martin, who has documented his battle with colorectal cancer since his diagnosis in 2020, delivered a final message in an  Instagram post  on Wednesday. "Hey, it's me, Tanner, if you're watching this, I am dead," he said. "I had a heck of a life....