instruction: Create a Dockerfile for fundamentals
output: ```dockerfile
  from this image.Finally, the -t flag tags your image. Think of this as a human-readable name for the final image. Since you named the image getting-started, you can refer to that image when you run a container.The . at the end of the docker build command tells Docker that it should look for the Dockerfile in the current directory.Start an app containerNow that you have an image, you can run the application in a container using the docker run command.Run your container using the docker run command and specify the name of the image you just created:
  
  $ docker run -d -p 127.0.0.1:3000:3000 getting-started
  The -d flag (short for --detach) runs the container in the background.
  This means that Docker starts your container and returns you to the terminal
  prompt. Also, it does not display logs in the terminal.The -p flag (short for --publish) creates a port mapping between the
  host and the container. The -p flag takes a string value in the format of
  HOST:CONTAINER, where HOST is the address on the host, and CONTAINER
  is the port on the container. The command publishes the container's port
  3000 to 127.0.0.1:3000 (localhost:3000) on the host. Without the port
  mapping, you wouldn't be able to access the application
  ```