Add signup table.

object/application.go

@@ -32,6 +32,7 @@ type Application struct {
 	EnablePassword  bool            `json:"enablePassword"`
 	EnableSignUp    bool            `json:"enableSignUp"`
 	Providers       []*ProviderItem `xorm:"varchar(10000)" json:"providers"`
+	SignupItems     []*SignupItem   `xorm:"varchar(1000)" json:"signupItems"`
 	OrganizationObj *Organization   `xorm:"-" json:"organizationObj"`
 
 	ClientId       string   `xorm:"varchar(100)" json:"clientId"`

object/init.go

@@ -67,6 +67,7 @@ func initBuiltInApplication() {
 		EnablePassword: true,
 		EnableSignUp:   true,
 		Providers:      []*ProviderItem{},
+		SignupItems:    []*SignupItem{},
 		RedirectUris:   []string{},
 		ExpireInHours:  168,
 	}

object/signup_item.go

@@ -0,0 +1,22 @@
+// Copyright 2021 The casbin Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package object
+
+type SignupItem struct {
+	Name     string `json:"name"`
+	Visible  bool   `json:"visible"`
+	Required bool   `json:"required"`
+	Rule     string `json:"rule"`
+}