title: mongoDB: find by embedded value
body: <p>I have some problems with mongoDB, i looked for an answer but i couldn't find anything
  that solves my problem....</p>
  
  <pre><code>db.coders.save( {
  'name': 'John', 
  'languages' : { 'php':'bad','java':'good','brainfuck':'very bad'} 
  });
  
  db.coders.save( {
  'name': 'Sarah', 
  'languages' : { 'php':'good','java':'bad','brainfuck':'very bad'} 
  });
  
  db.coders.save( {
  'name': 'Tom', 
  'languages' : { 'php':'very good','java':'good','brainfuck':'bad'} 
  });
  </code></pre>
  
  <p>now i want to find any coder that knows any language 'very good'...how?</p>