Flushing content blocks with Rails 4

Besides the big and shiny features that Rails 4 holds, there’s a lot of small improvements on several other sections of the Rails framework - helpers, core extensions, app configurations and more - that might not even hit the Changelogs but will somehow make our lifes easier in the future. One of these hidden gems that I’ve found recently is an improvement on the content_for helper to flush and replace previous chunks of HTML with new ones.