You have already activated rake 0.9.0, but your Gemfile requires rake 0.8.7

I thank to Dobry Den, cheers dude. but little more I had to do. here is solution (works for me). I had added

gem 'rake','0.8.7'

on Gemfile, which was not there, but my new version of rails automatically install rake(0.9.0).

after I had delete rake0.9.0 by gem uninstall rake and after doing bundle update rake , I can create and migrate database.

First, check to make sure that rake is mentioned in your Gemfile. If it's not, add it, and specify the version "you already activated".

Then, you'll need to tell bundle to update the rake version it's using for your app:

bundle update rake

It'll update your Gemfile.lock for you.

Where you are currently using rake commands like

rake db:migrate

Use this instead:

bundle exec rake db:migrate

this will be the case until the latest version of rails and/or rake work well together.