  We propose a new method to find gravity duals to a large class of
three-dimensional Chern-Simons-matter theories, using techniques from dimer
models. The gravity dual is given by M-theory on AdS_4\times Y_7, where Y_7 is
an arbitrary seven-dimensional toric Sasaki-Einstein manifold. The cone of Y_7
is a toric Calabi-Yau 4-fold, which coincides with a branch of the vacuum
moduli space of Chern-Simons-matter theories.
