fix: handle user activation email errors

- Wrap the activation email sending in a begin-rescue block
- Log error messages if sending fails
- Provide user feedback with an error message and render the new user form again

This change improves the user experience by handling potential
errors during the user activation email process. If an error
occurs, it logs the issue and informs the user to try again,
preventing confusion and enhancing the robustness of the
registration flow.

app/controllers/users_controller.rb

@@ -28,9 +28,15 @@ class UsersController < ApplicationController
       # flash[:success] = "Welcome to the Sample App!"
       # redirect_to @user
       # redirect_to user_url(@user)
-      @user.send_activation_email
-      flash[:info] = "Please check your email to activate your account."
-      redirect_to root_url
+      begin
+        @user.send_activation_email
+        flash[:info] = "Please check your email to activate your account."
+        redirect_to root_url
+      rescue => e
+        logger.error "User creation failed: #{e.message}"
+        flash[:error] = "Something went wrong. Please try again."
+        render "new", status: :unprocessable_entity
+      end
     else
       render "new", status: :unprocessable_entity
     end