Feature: Add web push notification permission in frontend (#766)

Add webpush notification permission in frontend

Co-authored-by: Sojan <sojan@pepalo.com>

app/builders/notification_subscription_builder.rb

@@ -0,0 +1,28 @@
+class NotificationSubscriptionBuilder
+  pattr_initialize [:params, :user!]
+
+  def perform
+    # if multiple accounts were used to login in same browser
+    move_subscription_to_user if identifier_subscription && identifier_subscription.user_id != user.id
+    build_identifier_subscription if identifier_subscription.blank?
+    identifier_subscription
+  end
+
+  private
+
+  def identifier
+    @identifier ||= params[:subscription_attributes][:endpoint] if params[:subscription_type] == 'browser_push'
+  end
+
+  def identifier_subscription
+    @identifier_subscription ||= NotificationSubscription.find_by(identifier: identifier)
+  end
+
+  def move_subscription_to_user
+    @identifier_subscription.update(user_id: user.id)
+  end
+
+  def build_identifier_subscription
+    user.notification_subscriptions.create(params.merge(identifier: identifier))
+  end
+end