no such file to load -- rack/openid

I am working on a rails gem which depends on rack/openid. But when I require it and fire up my application I get this error

no such file to load -- rack/openid

The gem is installed

$ gem list | grep openid
rack-openid (1开发者_如何学C.3.1, 1.2.0)
ruby-openid (2.1.8)

I've seen this question but it did NOT helped a lot.

Problem with require rack/openid in Rails 3 [native require work properly]

PS: I can require it from Irb just fine

It looks like you haven't added your Gem to the Gemfile, or you haven't added rack-openid as a dependency to your gem.

When Rails starts up, it uses bundler to set up the load path to match the Gemfile.lock file, so even a gem is installed locally you won't be able to require it if it isn't listed there.

Gemfile.lock is created by bundler based on the gems listed in Gemfile and their dependencies.

Make sure the gem you're working on specifies rack-openid as a dependency in its .gemspec, and then add gem 'my-gem-name' to your applications Gemfile (replace my-gem-name with whatever your gem is actually named).