Rails 5 - Google Page Speed Insights - 利用浏览器缓存

I've got a Rails 5 development site running on a public server. The project is also in development mode. I have been scanning the site with Google Page Speed Insights and one of the largest suggestions has been to leverage browser caching. So, I looked around on google and every answer says to use this code:I've got a Rails 5 development site running on