Add post image storage

internal/store/memory.go

@@ -209,6 +209,9 @@ func (m *Memory) CreatePost(_ context.Context, post *Post) error {
 	if err := preparePost(post); err != nil {
 		return err
 	}
+	if err := preparePostImages(post); err != nil {
+		return err
+	}
 	m.mu.Lock()
 	defer m.mu.Unlock()
 	if _, ok := m.users[post.AuthorID]; !ok {
@@ -287,6 +290,10 @@ func (m *Memory) UpdatePost(_ context.Context, post *Post) error {
 	if body == "" {
 		return fmt.Errorf("%w: body is required", ErrInvalidPost)
 	}
+	post.Body = body
+	if err := preparePostImages(post); err != nil {
+		return err
+	}
 	m.mu.Lock()
 	defer m.mu.Unlock()
 	existing, ok := m.posts[post.ID]
@@ -294,6 +301,7 @@ func (m *Memory) UpdatePost(_ context.Context, post *Post) error {
 		return sql.ErrNoRows
 	}
 	existing.Body = body
+	existing.Images = append([]PostImage(nil), post.Images...)
 	existing.UpdatedAt = time.Now().UTC().Format(time.RFC3339Nano)
 	*post = *clonePostWithAuthor(existing, m.users)
 	return nil
@@ -451,6 +459,7 @@ func clonePost(post *Post) *Post {
 		parentID := *post.ParentID
 		cp.ParentID = &parentID
 	}
+	cp.Images = append([]PostImage(nil), post.Images...)
 	cp.Replies = nil
 	return &cp
 }