I use a big 30 gallon container with egg cartons for housing. Throw some dog food in with the occasional fruit/vegetable. I spray mine every night with water, in some places with high humidity mold may be an issue, but its dry here so not really a problem. Also a heating pad under one side will bring the temps up and encourage breeding. Other than that leave them alone and theyll multiply like crazy.
** Only use dogfood for growing the colony. If your feeding them off, gutload them on something else for a couple days.