Ruby on Rails is a server-side web framework written in Ruby. It organizes an app with the Model-View-Controller (MVC) pattern, which has three parts.
The model holds the data and business logic, and talks to the database through Active Record.
The view is the presentation layer, usually HTML built from Embedded Ruby (ERB) templates.
The controller receives each request, asks the models for data and picks the view.
Rails also follows convention over configuration, so common tasks need little setup. Don't Repeat Yourself (DRY) keeps each piece of logic in one place, which makes code easier to maintain.
Rewriting in plainer words…
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