first version of doc for the nightly build.

doc/advanced/unittest.txt

@@ -172,12 +172,13 @@ Example:
 
 Whenever possible, unit tests should omit this parameter. Leaving-out the mode will ensure that unit tests use the default mode (defined in compile.mode.default_mode). This default_mode is set to the THEANO_DEFAULT_MODE environment variable, if it is present. If not, it defaults to 'FAST_RUN'.
 
-This allows the user to easily switch the mode in which unittests are run. For example the nightly-build system iterates over all modes.
+This allows the user to easily switch the mode in which unittests are run. For example the nightly-build system could iterates over all modes.
 
 >>> THEANO_DEFAULT_MODE=FAST_COMPILE nosetests
 >>> THEANO_DEFAULT_MODE=FAST_RUN nosetests
 >>> THEANO_DEFAULT_MODE=DEBUG_MODE nosetests
 
+We don't do this as the debug mode generate the same error or more then the two previous one.
 
 Using Random Values in Test Cases
 ---------------------------------

doc/internal/dev_start_guide.txt

@@ -42,7 +42,7 @@ As a developer, you should clone this repository like this:
 Nightly test
 ============
 
-WRITEME 
+Each night we execute all tests. The result is sent by email to one of the develloper and if it their is some change, he forward it to the mailing list. Otherwise we know that nothing changed from the last time it was emailed. He don't read its email each weekend, so their can be some delay. For more detail :ref:`see <metadocumentation_nightly_build>`.
 
 Setting up your environment
 ===========================

doc/internal/metadocumentation.txt

@@ -98,12 +98,27 @@ You can see a list of all `pylint messages
 <http://www.logilab.org/card/pylintfeatures>`__.
 
 
+.. _metadocumentation_nightly_build:
+
+The nightly build process.
+---------------------------------------
+
+The user lisa have a cronjob on the computer boltzmann. The cronjob execute the script ~/nightly_build/do_nightly_build_theano. This script make a an "hg pull -u" of theano and pylearn. Then it execute 
+
+>>> HEANO_DEFAULT_MODE=DEBUG_MODE /usr/bin/nosetests --with-coverage --cover-package=theano --cover-package=pylearn
+
+in the repository. The output is email to one of the developper.
+
+We can't email directly to the mailing list as it is emailed as the root user. We didn't found a way to have google groups accept email from a user without sending an email to it. As we don't have root control from this domain, we won't receive the email.
+
+Also, to have the crontab executed, the user must be logged onto the machine. The develloper that receive the email, keep a connection open to this machine.
+
 TO WRITE
 ---------------------------------------
 
 *There is other stuff to document here, e.g.:*
  * where the documentation is getting built, and epy.
  * How epydoc and sphinx are integrated
- * The nightly build process.
  * Explain the special magic in ./doc/scripts/docgen.py
  * We also want examples of good documentation, to show people how to write sphinx,
+