[doc] Update docker related information

The links to the images have been updated to use docker hub and there's
also a new paragraph about beat/beat.env.example>.

doc/develop.rst

@@ -78,20 +78,18 @@ execute algorithms or experiments.
 We use specific docker images to run user algorithms. Download the following
 base images before you try to run tests or experiments on your computer::
 
-  $ docker pull docker.idiap.ch/beat/beat.env.system.python:1.3.0
-  $ docker pull docker.idiap.ch/beat/beat.env.db.examples:1.4.0
-  $ docker pull docker.idiap.ch/beat/beat.env.client:2.0.0
-  $ docker pull docker.idiap.ch/beat/beat.env.cxx:2.0.0
+  $ docker pull beatenv/beat.env.db.examples:1.4.1r0
+  $ docker pull beatenv/beat.env.python:2.1.0r7
+  $ docker pull beatenv/beat.env.cxxdev:2.0.0r4
+  $ docker pull beatenv/beat.env.cxx:2.0.0r4
 
-Optionally, also download the following images to be able to re-run experiments
+Optionally, you can also download other images to be able to re-run experiments
 downloaded from the BEAT platform (not required for unit testing). These docker
 images corresponds to the python environment available on the platform. Keep in
 mind that at the moment you cannot use different environments to run each block
-when you are using BEAT locally (meaning not using the Docker executor)::
+when you are using BEAT locally unless using the Docker executor. These images
+can be found on the `beatenv docker hub repository`_.
 
-  $ docker pull docker.idiap.ch/beat/beat.env.python:1.1.0
-  $ docker pull docker.idiap.ch/beat/beat.env.python:2.0.0
-  $ docker pull docker.idiap.ch/beat/beat.env.db:1.4.0
 
 Before pulling these images, you should check the registry as there might have
 been new release (i.e. rX versions).
@@ -103,6 +101,21 @@ To run an experiment using docker you should specify the docker image when defin
 You can find more information about running experiments locally using different executors in the "Experiments" section of "beat.cmdline" in `BEAT documentation`_.
 
 
+Custom image development
+------------------------
+
+Scientific development evolving quickly, the platform provided runtime environments
+may not contain everything you need for your algorithms to run. In that case, you
+can prepare your own environment using the following git repository.
+
+  $ git clone https://gitlab.idiap.ch/beat/beat.env.example
+
+The examples provided there will allow you to build docker images suitable both
+for algorithm execution and if needed database handling.
+
+Instructions are provided in the repository.
+
+
 Documentation
 -------------
 

doc/links.rst

@@ -51,3 +51,4 @@
 .. _restructuredtext: http://docutils.sourceforge.net/rst.html
 .. _BEAT documentation: https://www.idiap.ch/software/beat/documentation
 .. _the docker website: https://docs.docker.com/engine/installation/
+.. _beatenv docker hub repository: https://hub.docker.com/u/beatenv