title: How can I make a tag system like stackoverflow.com?
body: <p>I'm going to make a website to post with tags. Tags can be up to five number of tags like at stackoverflow.com.</p>
  
  <p>Can anyone tell the tag system of StackOverflow? The relational database system with post and tag.</p>
  
  <p>Should I add a column in post table or should I create separate tag table for it? Tags can be separated by spaces or comma.</p>