Add server attribute to associate and disassociate a server to an address.

lib/fog/hp/models/compute/address.rb

@@ -12,6 +12,14 @@ module Fog
         attribute :fixed_ip
         attribute :instance_id
 
+        attr_accessor :instance_id
+
+        def initialize(attributes = {})
+          # assign server first to prevent race condition with new_record?
+          self.server = attributes.delete(:server)
+          super
+        end
+
         def destroy
           requires :id
 
@@ -19,14 +27,45 @@ module Fog
           true
         end
 
+        def server=(new_server)
+          if new_server
+            associate(new_server)
+          else
+            disassociate
+          end
+        end
+
         def save
           raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           data = connection.allocate_address.body['floating_ip']
           new_attributes = data.reject {|key,value| !['id', 'instance_id', 'ip', 'fixed_ip'].include?(key)}
           merge_attributes(new_attributes)
+          if @server
+            self.server = @server
+          end
           true
         end
 
+        private
+
+        def associate(new_server)
+          if new_record?
+            @server = new_server
+          else
+            @server = nil
+            self.instance_id = new_server.id
+            connection.associate_address(instance_id, ip)
+          end
+        end
+
+        def disassociate
+          @server = nil
+          unless new_record?
+            connection.disassociate_address(instance_id, ip)
+          end
+          self.instance_id = nil
+        end
+
       end
 
     end