title: Rails: What is the use of web servers (Apache / nginx / passenger)?
body: <p>Hi I've been learning rails for the past half year and have a few apps up on Heroku. So for me I thought deploying apps onto the world wide web was just as simple as <code>heroku push</code>. However, I just got my first internship doing Rails and one of my seniors is talking about Apache and Nginx and I'm not sure how they fit in the picture, since I thought apps consisted of only Rails + cloud app platform. I have looked it up but I still don't get how and where it affects my app life cycle. Can someone explain what/where/when of using web servers?</p>