Ruby app through Heroku

[Atul M.]

I am trying to build a basic Ruby app on Twilio and deploying through
Heroku, I get an error. Backtracing it, when I check my Heroku logs, I
see the following:

C:\AJ\twilioapp>heroku logs
/usr/ruby1.8.7/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`gem_orig
inal_require': no such file to load -- sinatra (LoadError)
from
/usr/ruby1.8.7/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31
:in `require'
from ./app.rb:1
from
/usr/ruby1.8.7/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31
:in `gem_original_require'
from
/usr/ruby1.8.7/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31
:in `require'
from config.ru:1

I did a quick search and tried running a 'Hello World' sinatra app and
it ran perfectly. Not sure why my Twilio is not working though.

Would you be kind enough to advise?