Add support for multiple authors and contributors

cmd/backend/articles_contributors.go

@@ -112,3 +112,14 @@ func (db *DB) UpdateArticleContributors(articleID int64, contributorIDs []int64)
 	}
 	return fmt.Errorf("error: %v unsuccessful retries for DB operation, aborting", TxMaxRetries)
 }
+
+func (db *DB) DeleteArticleContributors(articleID int64) error {
+	query := "DELETE FROM articles_contributors WHERE article_id = ?"
+
+	_, err := db.Exec(query, articleID)
+	if err != nil {
+		return fmt.Errorf("error deleting articles_contributors %v from DB: %v", articleID, err)
+	}
+
+	return nil
+}