Source :
/app
/Config Stores the configuration files
/Controllers Controllers determine the program flow
/Database Stores the database migrations and seeds files
/Filters Stores filter classes that can run before and after controller
/Helpers Helpers store collections of standalone functions
/Language Multiple language support reads the language strings from here
/Libraries Useful classes that don't fit in another category
/Models Models work with the database to represent the business entities.
/ThirdParty ThirdParty libraries that can be used in application
/Views Views make up the HTML that is displayed to the client.
/public Application assets that you add, like CSS, javascript, or images.
/upload Upload folder location
/system This directory stores the files that make up the framework, itself.