undefined method prawn - Githubissues

Hi every one, I'm getting this error

  require 'sinatra/prawn'
  .
  .
  .
  get '/export' do
    content_type 'application/pdf'
    prawn :pdf
  end

undefined method 'prawn' for #<Reports:xxxxxxxxxxxxx>

I'm using

Using Ascii85 (1.0.2)
Using diff-lcs (1.1.3)
Using growl (1.0.3)
Using listen (0.5.0)
Using thor (0.16.0)
Using guard (1.3.2)
Using guard-rspec (1.2.1)
Using hashery (2.0.1)
Using mysql (2.8.1)
Using ruby-rc4 (0.1.5)
Using pdf-reader (1.2.0)
Using ttfunk (1.0.3)
Using prawn (0.12.0)
Using rack (1.4.1)
Using rack-protection (1.2.0)
Using rack-test (0.6.1)
Using rb-fsevent (0.9.1)
Using rspec-core (2.11.1)
Using rspec-expectations (2.11.3)
Using rspec-mocks (2.11.2)
Using rspec (2.11.0)
Using sbfaulkner-sinatra-prawn (0.9.2.1)
Using sequel (3.39.0)
Using shotgun (0.9)
Using tilt (1.3.3)
Using sinatra (1.3.3)
Using sinatra-sequel (0.9.0)
Using bundler (1.2.0)

Thanks

sbfaulkner / sinatra-prawn