anchor.diff:  + Response 409 (application/json)
   
               {
  -                "message": "Email address already exists"
  +                "message": "Email address already exists."
               }
           
   ## Authentication [/authenticate]
  
positive.code:                     "cool"
                  ]
              }
  
  ### Update an existing item [PUT]
  
  
negative.code:             {
                  "id": 1,
                  "url": "http://www.domain.name/resource_normalized_by_server.html",
                  "title": "Title 1",
                  "image": "http://url/to_image.jpg",
                  "created_at": "2015-08-05 08:40:51+01:00",
                  "updated_at": "2015-08-06 08:40:51+01:00",
                  "tags": [
                      "friends",
                      "cool"
                  ]
              }
              
  + Response 400 (application/json)
  
          {
              "message": "tags field is required."
          }
              
  + Response 401 (application/json)
  
          {
              "message": "Not authenticated."
          }
          
  + Response 404 (application/json)
  
          {
              "message": "Item not found."
          }
          
  ### Delete and existing item [DELETE]
  
  + Request (application/json)
  
      + Headers
      
              Authorization: Bearer JSON_Web_Token
              
  + Response 204 (application/json)
  
  + Response 401 (application/json)
  
          {
              "message": "Not authenticated."
          }
  
  + Response 404 (application/json)
  
          {
              "message": "Item not found."
          }
          
  ## List Tags [/tags{?q}{?limit}{?offset}{?sort}]
  
  ### List tags [GET]
  
  + Parameters
      + q: `custom text` (string) - Search by custom text that may be included in other fields or not
      + limit: 10 (number) - Limit the number or returned results to a fixed number (Default: 10)
      + offset: 0 (number) - Offset to shift the results by. Default: 0
      + sort: `-tag,created_at` (string) - Sort returend list by one field or another or by comma delimited fields in ascending or descending order
  
  + Request (application/json)
      
      + Headers
      
              Authorization: Bearer JSON_Web_Token
  
  + Response 200 (application/json)
  
          [
              {
                  "tag": "friends",
                  "created_at": "2015-08-05 08:40:51+01:00"
              },
              {
                  "tag": "cool",
                  "created_at": "2015-08-05 08:40:51+01:00"
              }
          ]
          
  + Response 401 (application/json)
  
          {
              "message": "Not authenticated."
          }
  
  ## Delete taggs [/tags/{tag}]
  
  ### Delete tag [DELETE]
  
  If the tag is not associated with any items it will be deleted.
  
  + Parameters
      + tag: tag1 (string) - ID of an existing item
      
  + Request (application/json)
      
      + Headers
      
              Authorization: Bearer JSON_Web_Token
              
  + Response 204 (application/json)
  
  + Response 401 (application/json)
  
          {
              "message": "Not authenticated."
          }
          
  
  + Response 404 (application/json)
  
          {
              "message": "Tag not found."
          }
  
  + Response 409 (application/json)
  
          {
              "message": "Tag is in use by another item."
          }