[doc] keep on working on the documentation

doc/guide.rst

+.. py:currentmodule:: bob.learn.pytorch
+
+User's guide
+============
+
+DCGAN
+-----
+
+Conditional GAN
+---------------
+
+DR-GAN
+------

doc/index.rst

@@ -7,14 +7,16 @@ Welcome to bob.learn.pytorch's documentation!
 =============================================
 
 This module contains the implementation of different Generative Adversarial Networks (GAN)
-derived for face processing.
+used for face processing.
 
 If you would like to have an idea on the basic principles of GAN, you should first read the
 paper by Goodfellow et al.
 
 https://arxiv.org/abs/1406.2661
 
-Also, this package makes heavy use of pytorch_, so make sure you have it installed on your enviroment.
+This package makes heavy use of pytorch_, so make sure you have it installed on your environment. It also
+relies on bob_ (and in particular for I/O and databases interfaces), so you may want to refer 
+to their respective documentation.
   
 This package is basically organized as follows (some files are omitted for clarity purposes):
 
@@ -45,6 +47,8 @@ This package is basically organized as follows (some files are omitted for clari
 .. toctree::
    :maxdepth: 3
 
+   guide
+
    py_api
 
 Licensing