The Zapier Ruby SDK by David Peterson wraps the API to post to Slack and send an email to notify deployment completion. General usage includes configuration to choose a trigger and action and select a Web Hook account. Rails usage presents how to initiate with few lines of code.
Cloudways is a managed cloud hosting platform; Slack chatbots are capable of handling automatic messages. This tutorial by Ahmed Khan on the Cloudways blog shows readers how to create a Slack chatbot and connect it with the Cloudways API to automate tasks for a Cloudways hosted server.