Creates a group based on a field of Gravity Forms form.

functions.php

add_action("gform_after_submission", "my_gform_after_submission", 10, 2);

function my_gform_after_submission ( $entry, $form ) {

	$group_name = sanitize_text_field( trim( $entry['1'] ) ); // if the group's name is on the first field

	if ( $group = Groups_Group::read_by_name( $group_name ) ) {
		$group_id = $group->group_id;
	} else {
		$group_id = Groups_Group::create( array( 'name' => $group_name ) );
	}
	if ( $group_id ) {
		$user_id = get_current_user_id();
		Groups_User_Group::create( array ( 'user_id' => $user_id, 'group_id' => $group_id ) );
	}
}