feat: validate user availability

app/main.go

@@ -153,6 +153,7 @@ func main() {
 
 	http.HandleFunc("/addresses/upload-csv", adminMiddleware(handlers.CSVUploadHandler))
 	http.HandleFunc("/reports", adminMiddleware(handlers.ReportsHandler))
+
 	http.HandleFunc("/posts", adminMiddleware(handlers.PostsHandler))
 
 	http.HandleFunc("/api/validated-addresses", handlers.GetValidatedAddressesHandler)