Use kv datastore for auth (#272)

auth.ts

@@ -2,25 +2,8 @@ import NextAuth from 'next-auth'
 import Credentials from 'next-auth/providers/credentials'
 import { authConfig } from './auth.config'
 import { z } from 'zod'
-import { sql } from '@vercel/postgres'
 import { getStringFromBuffer } from './lib/utils'
-
-interface User {
-  id: string
-  name: string
-  email: string
-  password: string
-  salt: string
-}
-
-async function getUser(email: string): Promise<User | undefined> {
-  try {
-    const user = await sql<User>`SELECT * FROM users WHERE email=${email}`
-    return user.rows[0]
-  } catch (error) {
-    throw new Error('Failed to fetch user.')
-  }
-}
+import { getUser } from './app/login/actions'
 
 export const { auth, signIn, signOut } = NextAuth({
   ...authConfig,