Add a `Gemfile` for bundler support, add development dependencies to the gemspec.
Define an on_error hook

on_error hook is invoked when any exception occurs in the main action block
Update Gem in respect to new rails deprecation warning (https://github.com/rails/rails/pull/6739)
Added support for private callbacks
More descriptive test case for private callbacks
Ruby 1.8.7 compatibility
Better way to check for private methods
Merge remote-tracking branch 'dwbutler/master'. Include issue number
Merge remote-tracking branch 'ignar/master' #52 Use update_attributeS to solve new rails deprecation warning
Merge remote-tracking branch 'yanowitz/master' - Define an on_error hook

S. https://github.com/geekq/workflow/pull/47 for discussion and
explanation
Merge commit '435e212'

Conflicts:
	Gemfile
	workflow.gemspec
Version bump to 0.8.2
Adjust for the latest jeweler (1.8.4)

TODO: switch to the pure bundler soon
Version bump to 0.8.3
Regenerate gemspec for version 0.8.3
Version bump to 0.8.4
Regenerate gemspec for version 0.8.4
Version bump to 0.8.5
Version bump to 0.8.6
Switch to the new jeweler rake tasks

Avoid recursive dependency:

Fetching: workflow-0.8.4.gem (100%)
ERROR:  Error installing workflow:
    workflow requires workflow (>= 0)