Add a trivial ctor.
Add a trivial ctor.

cutelyst/grantlee,cutelyst/grantlee,simonwagner/grantlee,simonwagner/grantlee,simonwagner/grantlee,simonwagner/grantlee,simonwagner/grantlee,simonwagner/grantlee,cutelyst/grantlee,cutelyst/grantlee,cutelyst/grantlee