Ruby on Rails is an open source web application framework coded in Ruby that follows the Model View Controller (MVC) architecture. Ruby is an object oriented scripting language. Rails is a Model-View-Controller (MVC) framework based on Ruby and used for developing web applications. The Rails framework supports MySQL, PostgreSQL, SQL Server, DB2 and Oracle databases.
 
Here are key advantages to ROR:

     Speedier completion of projects, given the considerable decrease in the code lengths and volume.
     Work moves at a smoother pace, with fewer debugging pressure on the programmer.
     Independent threading facility, irrespective of the operating system and the highly portable nature that enhances the user-friendly nature of Ruby.
     Its built in web server WEBrick ameliorates Rubys performance in web applications and its excellent potentiality in loading the extension libraries dynamically with less maintenance.
     Database access is made more efficient and simpler with the help of most efficient database access libraries in Rails, called the Active records.
     Includes advanced application development paradigms like DRY (Dont Repeat Yourself) and Convention over configuration.
     It follows Agile Software Development Cycle.