improve registration and add oauth

app/controllers/sessions_controller.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class SessionsController < Devise::SessionsController
+  def create
+    if Docuseal.multitenant? && !User.exists?(email: sign_in_params[:email])
+      return redirect_to new_registration_path(sign_up: true, user: sign_in_params.slice(:email)),
+                         notice: 'Create a new account'
+    end
+
+    super
+  end
+end