title: A proper way to check if email exists sequelize (node js)?
body: <p>I'm starting with sequelize and to test it, i'm building a user registration system.<br>
  I have a UNIQUE constraint on the email FIELD, because i don't want multiple users to have the same email.
  To check if a email it's already registered i'm using this if statement:</p>
  
  <pre><code>           const emailExists = (await User.findOne()).where('email', email);
             if (emailExists) return res.json("Email already registered")
  </code></pre>
  
  <p>But i kinda feel that this isn't the correct approach to do it.
  Can anyone tell me if that's a better (what i think so) to check if the email is already registered?</p>
  
  <p>I also have this index: <code>"users_unique_lower_email_idx" UNIQUE, btree (lower(email::text))</code> on my table that doesn't seems to work when performing the check, if anyone know way and can anwer me i'd be glad.</p>