No route matches [GET] "/app1" - ruby-on-rails

Question

Rails.root: /home/chris/rails_projects/app1
I get the message about routes. my routes.rb files show:
I do not know how to approach this at all. I am using Ubuntu 12.04 in Virtualbox.
Rails.application.routes.draw do
# The priority is based upon order of creation: first created -> highest priority.
# See how all your routes lay out with "rake routes".
# You can have the root of your site routed with "root"
# root 'welcome#index'
# Example of regular route:
# get 'products/:id' => 'catalog#view'
# Example of named route that can be invoked with purchase_url(id: product.id)
# get 'products/:id/purchase' => 'catalog#purchase', as: :purchase
# Example resource route (maps HTTP verbs to controller actions automatically):
# resources :products
# Example resource route with options:
# resources :products do
# member do
# get 'short'
# post 'toggle'
# end
#
# collection do
# get 'sold'
# end
# end
# Example resource route with sub-resources:
# resources :products do
# resources :comments, :sales
# resource :seller
# end
# Example resource route with more complex sub-resources:
# resources :products do
# resources :comments
# resources :sales do
# get 'recent', on: :collection
# end
# end
# Example resource route with concerns:
# concern :toggleable do
# post 'toggle'
# end
# resources :posts, concerns: :toggleable
# resources :photos, concerns: :toggleable
# Example resource route within a namespace:
# namespace :admin do
# # Directs /admin/products/* to Admin::ProductsController
# # (app/controllers/admin/products_controller.rb)
# resources :products
# end
end

Answer 1

You need to create a controller and a view to direct your app somewhere.
Then you need to route your app to that action by editing your routes file. For example you can uncomment the line:
root 'welcome#index'
This will then mean that when you navigate to the root of your site at the root directory (/app1) will go to the welcome controller, to its index action.
To learn more, have a look at: http://guides.rubyonrails.org/routing.html#using-root

Answer 2

Routes
You need to define the routes your application will use, as follows:
#config/routes.rb
root 'application#index'
This will direct any of the "homepage" traffic to the following controller/action:
#app/controllers/application_controller.rb
Class ApplicationController < ActionController::Base
def index
end
end
--
Routing in Rails
You have to remember that Rails is an MVC-centric web application framework
This means every time you wish to access a "url", you need to define the "route" in your routes.rb file. The way to do this is to reference the relevant controller#actions in your routes file - using the resources method:
#config/routes.rb
root "application#index"
resources :controller_1, :controller_2
As Rails is object-orientated, the routes of your application will generally have to reflect the various resources it has inside. Most people try and define routes based on the presumed "flow" of the app - the truth is that you want to construct them around objects, which typically means controller and/or models