Update CONTRIBUTORS.md
Update CONTRIBUTORS.md

i made the authors as a list.
gerryhocks/redpen,kenhys/redpen,kenhys/redpen,tatamiya3/redpen,recruit-tech/redpen,recruit-tech/redpen,gerryhocks/redpen,recruit-tech/redpen,kenhys/redpen,johtani/redpen,johtani/redpen,tatamiya3/redpen,tatamiya3/redpen,redpen-cc/redpen,redpen-cc/redpen,johtani/redpen,jmoriya/redpen,kenhys/redpen,tatamiya3/redpen,redpen-cc/redpen,redpen-cc/redpen,gerryhocks/redpen,jmoriya/redpen,recruit-tech/redpen,redpen-cc/redpen,gerryhocks/redpen,jmoriya/redpen