adding distributed_by support from annotation in ddlog
adding distributed_by support from annotation in ddlog

sky-xu/deepdive,zifeishan/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,zifeishan/deepdive,zifeishan/deepdive,sky-xu/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,shahin/deepdive,zifeishan/deepdive,zifeishan/deepdive,shahin/deepdive