Grouping Immutable Deploy Data

The developer at Netlify updated the deploys page by grouping deploy data by date using Immutable.js. The data was coming from an API that didn't group it by date, but Redux and Immutable.js allowed for immutability of state to be maintained. The reducer function `groupByDate()` was created to group similar deploys with the created_at date as the key, using the `reduce()` function available in Immutable Lists. This resulted in a new data structure that made it easier to display the deploy data by date. The developer used JSX to map over the grouped deploy data and render it on the page.