fun getUserByEmail(email: String): UserModel{
            var user = UserModel()
            var firestoreDB = FirebaseFirestore.getInstance()
            firestoreDB.collection("users").document(email).get()
                .addOnSuccessListener { document ->
                    if(document == null)
                        Log.d("DUPA", "Brak takiego użytkownika")

                    else{
                        Log.d("DUPA", "Pobrano dane użytkownika")
                        //Log.d("DUPA", "Email: ${document["email"]}")
                        //Log.d("DUPA", "Name: ${document["firstName"]}")

                        user = UserModel(
                            email = document["email"].toString(),
                            firstName = document["firstName"].toString(),
                            phoneNumber = document["phoneNumber"].toString()
                        )

                        //Log.d("DUPA", "Email: ${user.email}")
                        //Log.d("DUPA", "Name: ${user.firstName}")
                    }

                }.addOnFailureListener {
                    Log.d("DUPA", "Nieudane zapytanie")
                }

            Log.d("DUPA", "Email: ${user.email}")
            Log.d("DUPA", "Name: ${user.firstName}")
            return user