[book] Improve PostgreSQL configuration section
* Do not advice for specific PostgreSQL version (point to meta-packages if
available in Linux distros);
* First mention packages from Linux distros, put the link to official postgres
documentation at the end;
Closes #2725302.
Web side development
====================
In this chapter, we will describe the core APIs for web development in
the *CubicWeb* framework.
.. toctree::
:maxdepth: 2
publisher
controllers
request
searchbar
views/index
rtags
ajax
js
css
edition/index
facets
internationalization
property
httpcaching
resource