anchor.diff:  ## Subscriptions Collection [/{tenantid}/servers/{serverid}/subscription]
   ### Create a new subscription [POST]
   This operation creates a new subcription associated to a rule
  +
  +Attributes:
  +
  +* `ruleId`:  is the key that represents the id of the rule, following the OpenStack Id format (e.g. 52415800-8b69-11e0-9b19-734f6f006e54).
  +* `url`:  the key whose value is the url to notify the action when the rule is fired.
  +
   + Parameters
       + tenantid (required, text, `d3fdddc6324c439780a6fd963a9fa148`) ... Alphanumeric `id` of the Tenant to perform action with. Has example value.
       + serverid (required, text, `52415800-8b69-11e0-9b19-734f6af67565`) ... Alphanumeric `id` of the server following the OpenStack ID format.
  
positive.code: ## Facts Collection [/{tenantid}/servers/{serverid}]
  ### Create new facts associated to a server [POST]
  This operation updates the context related to a specific server, identified with its serverId. The context information contains the description of the CPU, Memory, Disk and/or Network usages. This message follows the NGSI-10 information model but using JSON format and the response has no body.
  + Parameters
      + tenantid (required, text, `d3fdddc6324c439780a6fd963a9fa148`) ... Numeric `id` of the Tenant to perform action with. Has example value.
      + serverid (required, text, `52415800-8b69-11e0-9b19-734f6af67565`) ... Numeric `id` of the 
  
negative.code: ## Elasticity Rule Collection [/{tenantid}/servers/{serverid}/rules/{ruleid}]
  ### Update an elasticity rule [PUT]
  This operation allows to update the rule condition, the action or both or a specific server
  
  Attributes:
  
  * `name`: The value of the windowsize to be updated (must be an integer between 1 and the max_window_size value defined in the settings file).
  * `condition`: Condition is a JSON description with the attributes representing server measures with a value and an operator. 
  * `action`: It is a JSON description with the action to be performed if condition is taken place.
  
  
  + Parameters
      + tenantid (required, text, `d3fdddc6324c439780a6fd963a9fa148`) ... Alphanumeric `id` of the Tenant to perform action with. Has example value.
      + serverid (required, text, `52415800-8b69-11e0-9b19-734f6af67565`) ... Alphanumeric `id` of the server following the OpenStack ID format.
  