A JDBC driver that looks for environment variables to delegate to another JDBC driver.
E.g. if you set the JDBC url in your application to be jdbc:environment:0 it will look for environment variables of the format:
GUPPY_ENVIRONMENT.0.URL=
GUPPY_ENVIRONMENT.0.PROPERTY.1=name=value
GUPPY_ENVIRONMENT.0.PROPERTY.2=name2=value2