Add helper scripts
Fix paths used internally by the models
Add nginx and unicorn configuration sample files

- unicorn.rb may be used as-is
- nginx.conf is an example of a simple nginx setup
Fix the unicorn.rb file

- It now generates the absolute paths required for its initialization
- Update .gitignore (unicorn logs and socket files)
- Update dependencies (Gemfile and Gemfile.lock)
Update README.md