The directory structure of Rails includes the following:
-app/ - this is the folder that consists of controller, models and views of the appliation.
-config/- this folder consists of the configuration of the application that consists of runtime rules, routes, databases, etc.
-db/- this folder consists the database schema that is being currently used. It also has the information regarding the database migration.
-doc/- this is the folder that consists of all the documentation that is required to be used with the application.
-lib/- this folder consists of the extended modules and the libraries that is being used by the application
-log/- this folder consists of the logs that is being generated during the execution of the application.