How to: override devise default routes of sign in and sign out

routes.rb

MyApp::Application.routes.draw do
  # If you concern about SEO then send permanent redirect (301) on old routes to new routes
  # It is always better to do this setting in web server that is in nginx or apache. 
  # Here I am showing how to do it in rails routes file
  get '/users/sign_in', to: redirect("/sign-in")
  get '/users/sign_up', to: redirect("/sign-up")
 
  # Need to skip session and registration so that we can override them in devise_scope block
  # If we not do so then default route of devise continue to work
  devise_for :users, :skip => [:sessions, :registrations] 
 
  # Override all required routes which you uses. There are another routes
  # which devise provide with session and registration which we skipped
  # above.
  # for session we have overridden all routes i.e new, create and destroy
  # for registration we have overrides only new and create but
  # registration has following default routes
  # cancel_user_registration GET      /users/cancel(.:format)   registrations#cancel
  #        user_registration POST     /users(.:format)          registrations#create
  #    new_user_registration GET      /users/sign_up(.:format)  registrations#new
  #   edit_user_registration GET      /users/edit(.:format)     registrations#edit
  #                          PATCH    /users(.:format)          registrations#update
  #                          PUT      /users(.:format)          registrations#update
  #                          DELETE   /users(.:format)          registrations#destroy
  devise_scope :user do
    get    "sign-in",  to: "devise/sessions#new",         as: :new_user_session
    post   "sign-in",  to: "devise/sessions#create",      as: :user_session
    delete "sign-out", to: "devise/sessions#destroy",     as: :destroy_user_session
 
    get    "sign-up",  to: "devise/registrations#new",    as: :new_user_registration
    post   "sign-up",  to: "devise/registrations#create", as: :user_registration
  end
 
  resources :posts
  root 'posts#index'
end