Serial group rings of finite groups. $p$-solvability

We prove that for any finite $p$-solvable group $G$ with a cyclic $p$-Sylow subgroup and any field $F$ of characteristic $p$, the group ring $FG$ is serial. As a corollary for an arbitrary field we will produce a list of all groups of order $\leq 100$ whose group rings are serial.