Enhance database models with comments and table descriptions

- Added comments to various fields in the database models for better clarity and understanding.
- Implemented TableComment methods for several models to provide descriptive information about their purpose.
- Updated the AutoMigrate function to support setting table comments in the database.
- Improved overall documentation within the code to facilitate future maintenance and development.

internal/model/user.go

@@ -7,23 +7,27 @@ import (
 )
 
 type User struct {
-	ID        uint           `gorm:"primarykey" json:"id"`
-	CreatedAt time.Time      `json:"created_at"`
-	UpdatedAt time.Time      `json:"updated_at"`
-	DeletedAt gorm.DeletedAt `gorm:"index" json:"-"`
+	ID        uint           `gorm:"primarykey;comment:用户ID" json:"id"`
+	CreatedAt time.Time      `gorm:"comment:创建时间" json:"created_at"`
+	UpdatedAt time.Time      `gorm:"comment:更新时间" json:"updated_at"`
+	DeletedAt gorm.DeletedAt `gorm:"index;comment:删除时间" json:"-"`
 
-	MiniProgramID uint        `gorm:"index:idx_mini_open,priority:1" json:"mini_program_id"`
+	MiniProgramID uint        `gorm:"index:idx_mini_open,priority:1;comment:小程序ID" json:"mini_program_id"`
 	MiniProgram   MiniProgram `gorm:"foreignKey:MiniProgramID" json:"mini_program,omitempty"`
-	OpenID        string      `gorm:"size:100;index:idx_mini_open,priority:2" json:"open_id"`
-	UnionID       string      `gorm:"size:100" json:"union_id,omitempty"`
-	NickName      string      `gorm:"size:100" json:"nickname"`
-	AvatarURL     string      `gorm:"size:500" json:"avatar_url"`
-	Gender        int         `gorm:"default:0" json:"gender"`
-	Phone         string      `gorm:"size:20" json:"phone,omitempty"`
+	OpenID        string      `gorm:"size:100;index:idx_mini_open,priority:2;comment:微信OpenID" json:"open_id"`
+	UnionID       string      `gorm:"size:100;comment:微信UnionID" json:"union_id,omitempty"`
+	NickName      string      `gorm:"size:100;comment:昵称" json:"nickname"`
+	AvatarURL     string      `gorm:"size:500;comment:头像URL" json:"avatar_url"`
+	Gender        int         `gorm:"default:0;comment:性别(0未知/1男/2女)" json:"gender"`
+	Phone         string      `gorm:"size:20;comment:手机号" json:"phone,omitempty"`
 
-	SessionKey string `gorm:"size:100" json:"-"`
+	SessionKey string `gorm:"size:100;comment:会话key(用于Bearer Token)" json:"-"`
 }
 
 func (User) TableName() string {
 	return "users"
 }
+
+func (User) TableComment() string {
+	return "用户"
+}