Invoke a rake task from another rake task

invoke_rake_task.rake

namespace :app_task do
  desc 'run web task'
  task :run_web do
    # my web task logic here
  end 

  desc 'run backend task' 
  task :run_backend do
    # my backend task logic here
    # after this invoke other rake task
    Rake::Task['app_task:run_web'].invoke
  end
end