Fix error if ActiveRecord isn't present.

This solves a uninitialized constant error when using outside of Rails.
Merge pull request #54 from awmichel/fix-sinatra-error

Fix Uninitialized Constant Error with Sinatra
bump version, update changelog, add @awmichel to THANKS
warn if the rollbar test task's mock request doesn't return a 500 status code
Add sucker_punch to gemspec dev dependency.
Add sucker_punch test case to spec.
Implement sucker_punch integration.
Update Gemfiles to include sucker_punch.
Merge branch 'sucker-punch' of github.com:dlackty/rollbar-gem into dlackty-sucker-punch
move some gems into gemspec, only test sucker punch if not ruby 1.8.7
updating THANKS and upping version to 0.10.10
Set Configuration#use_sidekiq to `true` when used for consistency
Set Rollbar::Configuration attribute @use_sidekiq to value given by user
Added Sidekiq to gemspec development dependency
Fixed custom options passed to Rollbar::Configuration#use_sidekiq
merge #57 and fix gemspec conflict, bump version to v0.10.11
merge commits
make sure sidekiq isn't tested if ruby 1.8.7
Add info about sucker_punch
Merge pull request #58 from ixti/sucker_punch_info

Add info about sucker_punch