add appraisals gem.
typo fixed.
add appraisals config: support rails3.1, 3.2, and 4.0
make dummy project compatiable with rails3.1 and 3.2
update readme.
Gemfile.lock use rails3.1 as default.
update rails3.1 gemfile.lock.
update .travis.yml
add bundle install command to .travis.yml
update .travis.yml
update .travis.yml
update .travis.yml
Merge pull request #4 from saberma/saberma-enhancement/support-rails3.1-3.2

支持 rails3.1, 3.2 版本