Failed webhook should not cause UI error

RuntimeError in ClientsController#create

Unable to open stream: http://g5-configurator.dev/consume_feed;
getaddrinfo: nodename nor servname provided, or not known

Extracted source (around line #40):

    if url
      begin
        Webhook.post(url)
      rescue ArgumentError => e
        logger.error e
      end

app/models/client.rb:40:in `post_webhook'
app/models/client.rb:33:in `set_urn'
app/controllers/clients_controller.rb:20:in `create'