at least it 501s nicely

cmd/http/main.go

@@ -96,6 +96,14 @@ func Main() {
 				})
 				return
 			case "/api/lastnlines":
+				if r.Method != http.MethodPut {
+					http.NotFound(w, r)
+					return
+				}
+				var lines []string
+				if err := json.NewDecoder(r.Body).Decode(&lines); err != nil {
+					panic(err)
+				}
 				http.Error(w, "not done yet", http.StatusNotImplemented)
 				return
 			}