  Categorical aspects of the theory of modules over trusses are studied. Tensor
product of modules over trusses is defined and its existence established. In
particular, it is shown that bimodules over trusses form a monoidal category.
Truss versions of the Eilenberg-Watts theorem and Morita equivalence are
formulated. Projective and small-projective modules over trusses are defined
and their properties studied.
