Eval is evil
It's bad practice to require rubygems

http://tomayko.com/writings/require-rubygems-antipattern
It's bad practice to tell users to use sudo when installing gems
Remove hashie dependency
Only use client_supplied_id if provided by user
Move dependencies from Gemfile to gemspec
Relax faraday dependency to 0.7.6
Update specs to new rspec syntax
Require lowest supported rspec version