title: A good gem for filtering and searching?
body: <p>I have to make a website where every registered users can create posts (a post has_many tags for filtering) representing a product, and anybody can see the posts, can search for a specific word (in the post name, or post tags) and can apply filters (post tags).</p>
  
  <p>I repeat that any registered user can post, not only admins.</p>
  
  <p>What gem could I use?</p>