public static JdbiExtension postgres(EmbeddedPgExtension pg) {
        return JdbiPostgresExtension.instance(pg);
    }
Creates a new extension using a managed, embedded postgres database. Using this method requires the <code>de.softwareforge.testing:pg-embedded</code>
component and the postgres JDBC driver on the class path.
<p>
It references an embedded pg extension, which must be added to the class independently and can be managed as a per-class extension, not a per-method
extension:

<pre>{@code
    @RegisterExtension
    public static EmbeddedPgExtension pg = MultiDatabaseBuilder.instanceWithDefaults().build();

    @RegisterExtension
    public JdbiExtension postgres = JdbiExtension.postgres(pg);
}</pre>
<p>
This is the most efficient way to run multiple tests within the same class that use a postgres database.

@param pg Reference to an embedded postgres database. This extension must be separately added to the test class.
@return A {@link JdbiExtension} connected to a managed postgres data source.
@see JdbiPostgresExtension
testing/src/main/java/org/jdbi/v3/testing/junit5/JdbiExtension.java