Bump to v0.2.0
More precise language in documentation
Remove reference to private beta from README.md
Fix Gemfile instruction in README.md
Added path_prefix to configuration

Added path_prefix configuration option. This allows prefixing of all
file paths and is used when the Rails application is not in the root
folder of the repository.
Merge pull request #29 from adamphillips/path_prefix

Added path_prefix to configuration