[README] Update docker section with instructions for pulling and running the docker image.

README.md

@@ -8,7 +8,7 @@ artificial intelligence based software.
 ## Installation
 
 No binaries are provided at the moment. Installation must be done by either
-compiling the source code or building a [Docker](https://www.docker.com/) image.
+compiling the source code or using a [Docker](https://www.docker.com/) image.
 
 ### From source code
 
@@ -33,13 +33,26 @@ $ make test
 
 ### Docker image
 
-To build a [Docker](https://www.docker.com/) image for CAISAR, do the following:
+A ready-to-use [Docker](https://www.docker.com/) image of CAISAR is available on
+[Docker Hub](https://hub.docker.com). To retrieve such an image, do the
+following:
+```
+$ docker pull laiser/caisar:pub
+```
+
+Alternatively, a [Docker](https://www.docker.com/) image for CAISAR can be
+created locally by proceeding as follows:
 ```
 $ git clone https://git.frama-c.com/pub/caisar
 $ cd caisar
 $ make docker
 ```
 
+To run the CAISAR [Docker](https://www.docker.com/) image, do the following:
+```
+$ docker run -it laiser/caisar:pub sh
+```
+
 ## Usage
 
 To start using CAISAR, please run the command: