text: Avatars = new FS.Collection('avatars', {
    stores: [
      new FS.Store.GridFS('avatars')
    ],
    filter: {
      maxSize: 32000,
      allow: {
        contentTypes: ['image/*']
      }
    }
  });
  
  var isOwner = function(userId, file) {
    return userId && userId === file.userId;
  };
  
  Avatars.allow({
    insert: isOwner,
    update: isOwner,
    remove: isOwner,
    download: function() { return true; },
    fetch: ['userId']
  });
  
  Avatars.files.before.insert(function(userId, doc) {
    doc.userId = userId;
  });
  