title: mongoskin dynamic collection name error
body: <p>I need to insert into a Mongodb collection where the collection name is inside a variable.
  but it seems its not possible or my code is wrong.</p>
  
  <pre><code>db.collection(colname).insert(dbjson, function(err, result) {
      if (err) throw err;
      if (result) console.log('Added!');
  });
  </code></pre>
  
  <p>but it throw this error:</p>
  
  <pre><code>Error: collection name must be a String
      at Error (&lt;anonymous&gt;)
      at checkCollectionName
  </code></pre>
  
  <p>any idea on how could i deal with this error?
  thanks</p>