in order to uniquely identify a `associated_users` on must traverse the object graph into the `onsite` object and construct an artificial key.

it makes more sense to either flatten the structure or, more appropriately in my opinion, simply use a site key instead of duplicating data that, if desired, can be pulled from the `/sites` route.

this is an example of where a decent site key would come in handy, but if, as insisted, a mixed case string with, currently, spaces and who knows what else in the future, is what we have for a key then please surface that on the result.

the current structure is unnatural and the nested object graph complicates consumption unnecessarily.

Current:


    {
      "associated_users": [
        {
          "user_id": 242897,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 9272,
          "on_site": {
            "name": "Stack Overflow",
            "logo_url": "http://sstatic.net/so/img/logo.png",
            "api_endpoint": "http://api.stackoverflow.com",
            "site_url": "http://stackoverflow.com",
            "description": "Q&A for programmers",
            "icon_url": "http://sstatic.net/so/apple-touch-icon.png"
          },
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 38306,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 111,
          "on_site": {
            "name": "Server Fault",
            "logo_url": "http://sstatic.net/sf/img/logo.png",
            "api_endpoint": "http://api.serverfault.com",
            "site_url": "http://serverfault.com",
            "description": "Q&A for system administrators and IT professionals",
            "icon_url": "http://sstatic.net/sf/apple-touch-icon.png"
          },
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 31747,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 100,
          "on_site": {
            "name": "Super User",
            "logo_url": "http://sstatic.net/su/img/logo.png",
            "api_endpoint": "http://api.superuser.com",
            "site_url": "http://superuser.com",
            "description": "Q&A for computer enthusiasts and power users",
            "icon_url": "http://sstatic.net/su/apple-touch-icon.png"
          },
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 144906,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 1252,
          "on_site": {
            "name": "Stack Overflow Meta",
            "logo_url": "http://sstatic.net/mso/img/logo.png",
            "api_endpoint": "http://api.meta.stackoverflow.com",
            "site_url": "http://meta.stackoverflow.com",
            "description": "Q&A about Stack Overflow, Server Fault, and Super User",
            "icon_url": "http://sstatic.net/mso/apple-touch-icon.png"
          },
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        // stackapss  missing
        {
          "user_id": 14,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 3123,
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        }
      ]
    }

Proposed: (i would be happy to meet you half way and tolerate the nested `on_site` node if only we can get the site id on the root as shown)

    {
      "associated_users": [
        {
          "user_id": 242897,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 9272,
          "site_name": "Stack Overflow",
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 38306,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 111,
          "site_name": "Server Fault",
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 31747,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 100,
          "site_name": "Super User",
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 144906,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 1252,
          "site_name": "Stack Overflow Meta",
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        },
        {
          "user_id": 14,
          "user_type": "registered",
          "display_name": "code poet",
          "reputation": 3123,
          "email_hash": "df4a7fbd8a054fd6193ca0ee62952f1f"
        }
      ]
    }