I Got a Cheat Skill in Another World and Became Unrivaled in The Real World, Too, Vol. 1 LN

A door to another world stretches out before a boy who-s beenbrutally bullied all his life. This alternate reality grants him access to allsorts of things, like cheat skills and a portal that lets him travel between hisold and new worlds! Can this class loser turn his life around back home...?