Nullifies instead of emptying user

app/models/user.rb

@@ -151,7 +151,7 @@ class User < ActiveRecord::Base
     self.update(
       erase_reason: erase_reason,
       username: nil,
-      email: "",
+      email: nil,
       unconfirmed_email: nil,
       document_number: nil,
       phone_number: nil,

spec/models/user_spec.rb

@@ -320,7 +320,7 @@ describe User do
 
       expect(user.username).to be_nil
 
-      expect(user.email).to be_empty
+      expect(user.email).to be_nil
       expect(user.unconfirmed_email).to be_nil
       expect(user.document_number).to be_nil
       expect(user.phone_number).to be_nil