class Falcon::Configuration

def add(name, *parents, &block)
	raise KeyError.new("#{name} is already set", key: name) if @environments.key?(name)
	
	environments = parents.map{|name| @environments.fetch(name)}
	
	parent = Build::Environment.combine(*environments)
	
	@environments[name] = Build::Environment.new(parent, name: name, &block)
end