added db tutorial (mapping) back to guidelist table of contents
added db tutorial (mapping) back to guidelist table of contents

theoryno3/pygr,theoryno3/pygr,GenDataPro/pygr,theoryno3/pygr,RitwikGupta/pygr,GenDataPro/pygr,RitwikGupta/pygr,GenDataPro/pygr,RitwikGupta/pygr,cjlee112/pygr,cjlee112/pygr,cjlee112/pygr,cjlee112/pygr