I follow your book "Rails 101" but not working.

[hkftwe]

I following version was published on 2014-06-10.
First, I following the book Ch 1.0:

• gem install bootstrappers -v=4.2.1
• bootstrappers groupme

Then, Ch1.1:

• rails g model group title:string description:text

But I get result below:
/Users/MHK/Dropbox/workspace_rails/groupme/config/environments/development.rb:1:in <top (required)>': undefined methodconfigure' for #Groupme::Application:0x007fefcb510960 (NoMethodError)
from /Users/MHK/.rvm/gems/ruby-2.0.0-p598/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:in require' from /Users/MHK/.rvm/gems/ruby-2.0.0-p598/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:inblock in require'
from /Users/MHK/.rvm/gems/ruby-2.0.0-p598/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:213:in load_dependency' ... from /Users/MHK/.rvm/gems/ruby-2.0.0-p598/gems/activesupport-4.0.0/lib/active_support/dependencies.rb:228:inrequire'
from /Users/MHK/.rvm/gems/ruby-2.0.0-p598/gems/railties-4.0.0/lib/rails/application.rb:189:in require_environment!' from /Users/MHK/.rvm/gems/ruby-2.0.0-p598/gems/railties-4.0.0/lib/rails/commands.rb:45:in<top (required)>'
from bin/rails:4:in require' from bin/rails:4:in

'

[FrankFang]

+1 NoMethodError

~/R/groupme ❯❯❯ rails -v    
Rails 4.0.0
~/R/groupme ❯❯❯ ruby -v
ruby 2.0.0p643 (2015-02-25 revision 49749) [x86_64-darwin14.1.0]