title: searching an array deep inside a mongo document
body: <p>in my mongo collection called pixels, I have documents like the sample 
  I'm looking for a way to search in the actions.tags part of the documents?  </p>
  
  <pre><code>db.pixelsactifs.actions.find({tags:{$in : ["Environnement"]}})
  db.pixelsactifs.find({actions.tags:{$in : {Environnement}})
  </code></pre>
  
  <p>doesn't work. I'm also looking for the PHP equivalent ?</p>
  
  <p>I'm also asking myself should I make an "actions" collection instead of putting everything inside one document
  I'm new to mongo so any good tutorial on structuring the db would be great</p>
  
  <p>Thanks for the insight</p>
  
  <pre><code>{
    "_id": { $oid": "51b98009e4b075a9690bbc71" },
    "name": "open Atlas",
    "manager": "Tib Kat",
    "type": "Association",
    "logo": "",
    "description": "OPEN ATLAS",
    "actions": [
      {
        "name": "Pixel Humain",
        "tags": [ "Toutes thémathiques" ],
        "description": "le PH agit localement",
        "images": [],
        "origine": "oui",
        "website": "www.echolocal.org"
      }
    ],
    "email": "my@gmail.com",
    "adress": "102 rue",
    "cp": "97421",
    "city": "Saint louis",
    "country": "Réunion",
    "phone": "06932"
  }
  </code></pre>