Defined require_user_signed_in filter in application controller

app/controllers/application_controller.rb

@@ -2,4 +2,25 @@ class ApplicationController < ActionController::Base
   # Prevent CSRF attacks by raising an exception.
   # For APIs, you may want to use :null_session instead.
   protect_from_forgery with: :exception
+
+  private
+  
+  #-> Prelang (user_login:devise)
+  def require_user_signed_in
+    unless user_signed_in?
+
+      # If the user came from a page, we can send them back.  Otherwise, send
+      # them to the root path.
+      if request.env['HTTP_REFERER']
+        fallback_redirect = :back
+      elsif defined?(root_path)
+        fallback_redirect = root_path
+      else
+        fallback_redirect = "/"
+      end
+
+      redirect_to fallback_redirect, flash: {error: "You must be signed in to view this page."}
+    end
+  end
+
 end