Add postgres exporter image to README (#581)
Add postgres exporter image to README (#581)


GoogleCloudPlatform/click-to-deploy,GoogleCloudPlatform/click-to-deploy,GoogleCloudPlatform/click-to-deploy,GoogleCloudPlatform/click-to-deploy,GoogleCloudPlatform/click-to-deploy,GoogleCloudPlatform/click-to-deploy