Make isValid a method and add skeleton for createVote

cmd/web/routes.go

@@ -17,6 +17,7 @@ func (app *application) routes() http.Handler {
 	mux := http.NewServeMux()
 
 	mux.HandleFunc("POST /election", app.createElection)
+	mux.HandleFunc("POST /vote", app.createVote)
 
 	standard := alice.New(app.recoverPanic, app.logRequest)
 	return standard.Then(mux)