This resolves an exception for 'Rack::Lint::LintError: header key must be a string, was Symbol'
Merge pull request #27 from jamesbrink/fix_rack_lint_exception

Fix Rack::Lint exception
[Closes #34] Update gemfile.lock
Merge pull request #35 from jamesbrink/gem_updates

[Closes #34] Update gemfile.lock
Updated Docker container to use unicorn.