Here is the error I get:
sergio@sergio-VirtualBox:~/blog$ rake db:create
rake aborted!
Could not find a JavaScript runtime. See https://github.com/sstephenson/ex
I had the same error, but then I reinstalled Ruby193 with all the checkboxes (Tc/Tk, associate rb, and add to PATH).
And then deleted the GEMFile.lock
Edited the Gemfile whereever I saw gem therubyracer, I changed it to: gem therubyracer, :platform => :ruby
Then bundle install
Then rake db:drop
Then rake db:create
Then rake db:migrate
and so on