[openstack|identity] Added function to add user to a tenant

lib/fog/openstack/identity.rb

@@ -37,6 +37,7 @@ module Fog
       request :delete_user
       request :get_user_by_id
       request :get_user_by_name
+      request :add_user_to_tenant
 
       request :list_endpoints_for_token
       request :list_roles_for_user_on_tenant

lib/fog/openstack/models/identity/tenant.rb

@@ -43,6 +43,10 @@ module Fog
             connection.create_tenant(attributes).body['tenant'])
           self
         end
+
+        def add_user(user_id, role_id)
+          connection.add_user_to_tenant(self.id, user_id, role_id)
+        end  
       end # class Tenant
     end # class OpenStack
   end # module Identity

lib/fog/openstack/requests/identity/add_user_to_tenant.rb

@@ -0,0 +1,29 @@
+module Fog
+  module Identity
+    class OpenStack
+      class Real
+        def add_user_to_tenant(tenant_id, user_id, role_id)
+          request(
+            :expects => 200,
+            :method  => 'PUT',
+            :path    => "/tenants/#{tenant_id}/users/#{user_id}/roles/OS-KSADM/#{role_id}"
+          )
+        end
+      end # class Real
+
+      class Mock
+        def add_user_to_tenant(tenant_id, user_id, role_id)
+          response = Excon::Response.new
+          response.status = 200
+          response.body = {
+            'role' => {
+              'id' => '503df61a99d6461fb247cdb6a3f3a4dd',
+              'name' => 'admin'
+            }
+          }
+          response
+        end # def add_user_to_tenant
+      end # class Mock
+    end # class OpenStack
+  end # module Identity
+end