  We construct a Grothendieck-Witt space for any stable infinity category with
duality. If we apply our construction to perfect complexes over a commutative
ring in which 2 is invertible we recover the classical Grothendieck-Witt space.
Our Grothendieck-Witt space is a grouplike E-infinity space which is part of a
genuine C_2-spectrum, the connective real K-theory spectrum.
