feat: implement watch for monitoring chat messages

- Added a new command handler for /watch that allows users to listen to messages from a specified chat and save them according to storage rules.
- Introduced filtering options for messages using regular expressions.
- Implemented functionality to start and stop watching chats, including error handling for invalid inputs and user settings.
- Created a new utility package for message element handling related to the watch feature.
- Updated the user model to manage watched chats, including methods to add, remove, and check if a chat is being watched.

database/user.go

@@ -1,6 +1,10 @@
 package database
 
-import "context"
+import (
+	"context"
+
+	"gorm.io/gorm/clause"
+)
 
 func CreateUser(ctx context.Context, chatID int64) error {
 	if _, err := GetUserByChatID(ctx, chatID); err == nil {
@@ -11,19 +15,16 @@ func CreateUser(ctx context.Context, chatID int64) error {
 
 func GetAllUsers(ctx context.Context) ([]User, error) {
 	var users []User
-	err := db.Preload("Dirs").
-		WithContext(ctx).
-		Preload("Rules").
+	err := db.WithContext(ctx).
+		Preload(clause.Associations).
 		Find(&users).Error
 	return users, err
 }
 
 func GetUserByChatID(ctx context.Context, chatID int64) (*User, error) {
 	var user User
-	err := db.
-		Preload("Dirs").
-		WithContext(ctx).
-		Preload("Rules").
+	err := db.WithContext(ctx).
+		Preload(clause.Associations).
 		Where("chat_id = ?", chatID).First(&user).Error
 	return &user, err
 }
@@ -36,5 +37,16 @@ func UpdateUser(ctx context.Context, user *User) error {
 }
 
 func DeleteUser(ctx context.Context, user *User) error {
-	return db.WithContext(ctx).Unscoped().Select("Dirs", "Rules").Delete(user).Error
+	return db.WithContext(ctx).
+		Unscoped().
+		Select(clause.Associations).
+		Delete(user).Error
 }
+
+func GetUserByID(ctx context.Context, id uint) (*User, error) {
+	var user User
+	err := db.WithContext(ctx).
+		Preload(clause.Associations).
+		Where("id = ?", id).First(&user).Error
+	return &user, err
+}