Update readme.md
Update readme.md

Example added for indexing nested models
hdngr/mongoosastic,mongoosastic/mongoosastic,hdngr/mongoosastic,teambition/mongoosastic,mallzee/mongoosastic,avastms/mongoosastic,avastms/mongoosastic,hdngr/mongoosastic,guumaster/mongoosastic,teambition/mongoosastic,guumaster/mongoosastic,mongoosastic/mongoosastic,ennosol/mongoosastic,francesconero/mongoosastic,mallzee/mongoosastic,guumaster/mongoosastic,francesconero/mongoosastic,mongoosastic/mongoosastic,ennosol/mongoosastic,mallzee/mongoosastic