A roundtable on affordable housing will be held in Bethel tonight.  The discussion will be held at 6:30pm at the municipal center in response to concerns from residents over developments.  Panelists will discuss the state's 8-30g law, which allows developers to bypass local zoning regulations if a percentage of their housing is designated as affordable.  The state Housing Commissioner, a community development specialist and the town planner will be joined on the panel by  First Selectman Matt Knickerbocker, Planning and Zoning Commission chair Pat Rist and state Representative Raghib Allie-Brennan.