If there is a finite group $G$ with a cyclic normal subgroup $C_n$, one can describe the indecomposable representations of $G$ through induction. How does $Ind_{C_n}^G$ decompose? For representations over fields, I know that Clifford's theory whould help. But what happens if the representations should be over a ring? I am interested expecially in the p-adic ring $Z_p$.