Add simple class to try to encapsulate DB bulk insertion.
Add simple class to try to encapsulate DB bulk insertion.


Former-commit-id: 51c56cb27ee676b9e8d29d5fc4f50151b6ce7925 [formerly 51c56cb27ee676b9e8d29d5fc4f50151b6ce7925 [formerly 46f373f439787792aaf350fefa58f144276381d5]]
Former-commit-id: 815338b775c1f30f0ff7d729602c1c010a72e33b
Former-commit-id: 5447a2dbffe423bcb17bca595adc2b1783867194
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine