heroku run rails

Language: Ruby.

1. heroku: heroku is a command-line tool that allows developers to deploy, manage, and scale applications on the Heroku platform.

2. run: The run command is used to run a one-off process on the Heroku platform. This can be used to execute any command in the context of your Heroku application.

3. rails: rails is a web application framework written in the Ruby programming language. It provides a set of tools and conventions for building web applications.

When you combine these three commands together (heroku run rails), you are instructing Heroku to run the rails command within the context of your Heroku application. This can be useful for tasks such as running database migrations, executing custom rake tasks, or running tests on your application.

Please note that the above explanation is based on the information provided and assumes a basic understanding of Ruby and the Heroku platform.