79-adding-i18n-polish

Added internationalization support with default yml file for Polish language. Also define Polish as default.
#47 Add header with menu
Merge pull request #9 from gotar/47-menu-building

#47 Add header with menu
Moved I18n config to seperate file in initializers folder.

[#79]
Merge pull request #15 from gotar/79-adding-i18n-polish

79-adding-i18n-polish
update Gemfile.lock