title: Firebase Query Double Nested
body: <p>Given the data structure below in firebase, i want to run a query to retrieve the blog 'efg'.  I don't know the user id at this point.</p>
  
  <pre><code>{Users :
       "1234567": {
            name: 'Bob',
            blogs: {
                 'abc':{..},
                 'zyx':{..}
            }
       },
       "7654321": {
            name: 'Frank',
            blogs: {
                 'efg':{..},
                 'hij':{..}
            }
       }
  }
  </code></pre>