This functionality is enabled by default.
ONGR provides the ability to override container parameters by specifying them in your environment. ONGR will grab all variables predefined with ONGR__ and set it as a parameter in the service container. Double underscores are replaced with a period, as a period is not a valid character in an environment variable name. Note that unlike Symfony environment variables, we override parameters after everything is loaded i.e. your parameters in configuration files will be overwritten.