Remove “www” from website link

So, I have a rails project deployed using apache server. Unfortunately the domain name is not registered with www. So if I do https://mydoin.com it works but https://www.mydoin.com doesn't. Now what I need is that, if someone use this url with www https://www.mydoin.com then I want to remove www from the url. How can I do this? I am using Ubuntu 16.04 and apache 2.4.