The method you are looking for is instance_variable_set. So:
hash.each { |name, value| instance_variable_set(name, value) }
Or, more briefly,
hash.each &method(:instance_variable_set)
If your instance variable names are missing the “@” (as they are in the OP’s example), you’ll need to add them, so it would be more like:
hash.each { |name, value| instance_variable_set("@#{name}", value) }