gem install not creating lib/ - ruby

Question

There's only one error I get when installing my custom gem: File not found: lib ERROR: While generating documentation
The install continues and says gem installed successfully. However, when I require 'boxes' I get LoadError: no such file to load -- boxes and when I look into the gem directory I notice that there is no lib/ folder in the installed gem. I'm not sure why this is or how to debug it. Any pointers? Below is my gemspec file.
# -*- encoding: utf-8 -*-
lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require 'boxes/version'
Gem::Specification.new do |gem|
gem.authors = ["Name"]
gem.email = ["http://somedomain.com"]
gem.description = %q{Boxes, a Sass framework}
gem.summary = %q{Boxes is a modular Sass-based framework that is heavily configurable, extremely modular and works as a Sass and a CSS Framework}
gem.homepage = "http://somedomain.com"
gem.files = `git ls-files`.split($\)
gem.executables = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
gem.test_files = gem.files.grep(%r{^(test|spec|features)/})
gem.name = "boxes"
gem.require_paths = ["lib"]
gem.version = Boxes::VERSION
gem.license = "MIT"
gem.add_dependency "sass", [">= 3.2.0"]
gem.add_development_dependency "rake"
end
I'm new at ruby, and I'm just creating my first gem here, so please bear with me.

Answer 1

One thing I noticed is that on line 1, you're defining "lib" as "../lib", though in gem.require_paths "lib" is in the current directory. Is that true?
Another thing to look for is that lib is not in .gitignore, as you're using git ls-files for defining gem.files
edit
Noticed in your gemfile that you're using ruby 1.8.7, make sure you require 'rubygems' before you require your gem