custom_id and name are required. They must be unique for the given resource type for the game to which they belong.custom_id: This is your key to the resource and is used for identification via the API. Currently, it can be set to any combination of alphanumeric characters, underscore, hyphen, period, and tilde and cannot exceed 255 characters.name: This is your way of giving your resource a friendly name. It's expected that this property might be used when displaying the given resource to your players. It can be set to any string value but may not exceed 255 characters.description: While not required, this property allows you to give a friendly description of the given resource. As with name, it's expected that this property might be used when displaying the resource to your players. Currently, it can be set to any string value, but may not exceed 255 characters.custom_data: This is a property that allows you to associate custom data with the given resource. You may want to associate image URLs with achievements, for example. Currently, it can be set to any valid JSON string that does not exceed 1024 characters.custom_data keys: a-z, A-Z, and underscore.custom_data, but there is a limit of 10 when using custom data references.