We construct a flat model structure on the category ${_{\mathcal {Q},\,R}\mathsf {Mod}}$
of additive functors from a small preadditive category $\mathcal {Q}$
satisfying certain conditions to the module category ${_{R}\mathsf {Mod}}$
over an associative ring $R$
, whose homotopy category is the $\mathcal {Q}$
-shaped derived category introduced by Holm and Jørgensen. Moreover, we prove that for an arbitrary associative ring $R$
, an object in ${_{\mathcal {Q},\,R}\mathsf {Mod}}$
is Gorenstein projective (resp., Gorenstein injective, Gorenstein flat, projective coresolving Gorenstein flat) if and only if so is its value on each object of $\mathcal {Q}$
, and hence improve a result by Dell'Ambrogio, Stevenson and Šťovíček.