CEDAR RAPIDS — A housing project devoting 10 percent of its units to permanent housing for the chronically homeless was approved Monday for $8 million in federal housing tax credits. The Crestwood Ridge Apartments, destined for 1200 Edgewood Road NW adjacent to Fire Station No. 3, will have four market-rate units, 36 units for people earning 60 percent of the median household income and five more “supportive housing” units for people earning 30 percent of the median income, according to the developer.“This is really a permanent rental home, not transitional housing, not a shelter,” Justin Eilers, housing manager for CommonBond Communities, said of the supportive units.