Fixed file insert

src/endpoints/bettwaage.py

@@ -12,7 +12,7 @@ file_path = "bettwaage.csv"
 
 def add_line_to_history(line: str) -> None:
     with open(file_path, "+a", encoding="UTF-8") as fp:
-        fp.writelines([line])
+        fp.write(f"{line}\n")
 
 
 @router.get("/file")