Todd Spangler NY Digital EditorRoku, in another opportunistic programming pickup, will bring comedy series “Children Ruin Everything” to U.S. audiences — streaming for free on the Roku Channel — in an exclusive pact with production company New Metric Media.The new half-hour comedy is created by Kurt Smeaton (“Schitt’s Creek,” “Kim’s Convenience”) and will air on Bell Media’s CTV network in Canada next spring.