title: remove query in mongodb by _id with nodejs
body: <p>removing a row in mongodb isn't seem to be that easy as in SQL lol, well, my issue is that I cant remove a row by the _id because the _id contains an obj <code>ObjectId</code>, that's the row in the db,</p>
  
  <pre><code>{
      "_id" : ObjectId("541ec60e41b46b841adde31e"),
      "name" : "TT"
  }
  </code></pre>
  
  <p>and this is how I'm trying to remove it,</p>
  
  <pre><code>db.books.remove({ _id: book_id}, function(err, delete) {
      if(err)
          console.log("ERROR!", err);
  
      console.log("deleted  ", delete);
  });
  </code></pre>
  
  <p>I've no idea how to pass the <code>book_id</code> so the query will run as expected,
  hope you guys will be able to help me find a solution for this one.
  thanks!</p>