How to save user to firestore while signup

Question

I'm trying to save the user to the users collection on firestore when user sign up using github. But unfortunately I was not able to do that. I'm using firebase v9

useSignUp hook code(this runs when user click on signup button)

import { GithubAuthProvider, signInWithPopup } from "firebase/auth"
import { useState } from "react"
import { auth } from "../firebase/config"
import { useAuthContext } from "./useAuthContext"

export const useSignup = () => {
  const [error, setError] = useState(false)
  const provider = new GithubAuthProvider()
  const { dispatch } = useAuthContext()

  const signup = () => {
    setError(null)
    signInWithPopup(auth, provider)
      .then(async (result) => {
        const user = result.user
        dispatch({ type: "LOGIN", payload: user })
      })
      .catch((error) => {
        const errorMessage = error.message
        console.log(errorMessage)
      })
  }
  return { error, signup }
}

AuthContext Code:

import { createContext, useReducer, useEffect } from "react"
import { auth } from "../firebase/config"
import { onAuthStateChanged } from "firebase/auth"
import { createUserProfileDocument } from "../firebase/createUserProfileDocument"

export const AuthContext = createContext()

export const authReducer = (state, action) => {
  switch (action.type) {
    case "LOGIN":
      return { ...state, user: action.payload }
    case "LOGOUT":
      return { ...state, user: null }
    case "AUTH_IS_READY":
      return { user: action.payload, authIsReady: true }
    default:
      return state
  }
}

export const AuthContextProvider = ({ children }) => {
  const [state, dispatch] = useReducer(authReducer, {
    user: null,
    authIsReady: false,
  })

  useEffect(() => {
    const unsubscribe = onAuthStateChanged(auth, (user) => {
      dispatch({ type: "AUTH_IS_READY", payload: user })
    })
    return unsubscribe
  }, [])

  return (
    <AuthContext.Provider value={{ ...state, dispatch }}>{children}</AuthContext.Provider>
  )
}