活动记录Ruby on Rails错误

Question

I have not gone too far with the development of the application.
i just did rails new app -d mysql and i did rails s loaded my browser.

Rails homepage loaded and I went inside my app folder, http://localhost:3000/demo/index and surprised to see this error ActiveRecord::ConnectionNotEstablished .
Please suggest some good way to get out of this and continue with my further development.

OS is Windows 7, I already installed mysql adapter and tried many solutions over the stackoverflow similar questions. None are solving my issue. I request serious help.
My database.yml looks like this with regards to development:

development:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: app_development
  pool: 5
  username: root
  password: pass
  host: localhost

Answer 1

After creating application, create database using below command

 rake db:create

and then start server using rails s

Answer 2

I switched to Ubuntu after trying number of methods to solve the issue on windows. Solved.