def properties_hash(properties, special_properties)
      properties.inject({}) do |props, (key, value)|
        key = "$#{key}" if special_properties.include?(key.to_s)
        value = value.to_i if value.class == Time
        props[key.to_sym] = value
        props
      end
    end
def properties_hash(properties, special_properties)
      properties.inject({}) do |props, (key, value)|
        key = "$#{key}" if special_properties.include?(key.to_s)
        value = value.to_i if value.class == Time
        props[key.to_sym] = value
        props
      end
    end
Walk through each property and see if it is in the special_properties.
 If so, change the key to have a $ in front of it.