Make atom feed compatible with multiple authors

cmd/backend/atom.go

@@ -51,12 +51,18 @@ func GenerateAtomFeed(c *Config, db *DB) (*string, error) {
 			entry.Links[linkID].Type = "image/webp"
 		}
 
-		user, err := db.GetUser(c, article.AuthorID)
+		authors, err := db.GetArticleAuthors(c, article.ID)
+		if err != nil {
+			return nil, fmt.Errorf("error getting article's authors for Atom feed: %v", err)
+		}
+		for _, author := range authors {
+			user, err := db.GetUser(c, author.ID)
 			if err != nil {
 				return nil, fmt.Errorf("error getting user info for Atom feed: %v", err)
 			}
 			authorID := entry.AddAuthor(atom.NewPerson(user.FirstName + " " + user.LastName))
 			entry.Authors[authorID].URI = c.Domain + "/image/serve/" + user.ProfilePicLink
+		}
 
 		tags, err := db.GetArticleTags(article.ID)
 		if err != nil {