[server] Make connection pooler configurable and set better default values
Drop the configuration connections-pool-size and add new configurations options:
* connections-pool-min-size. Set to 0 by default so we open connections only
when needed. This avoid opening min-size*processes connections at startup,
which is, it think, a good default.
* connections-pool-max-size. Set to 0 (unlimited) by default, so we move the
bottleneck to postgresql.
* connections-idle-timeout. Set to 10 minutes. I don't have arguments about
this except that this is the default in pgbouncer.
======================
Continuous Integration
======================
Jenkins
=======
A public instance of jenkins is used to test CubicWeb and its cubes :
* https://jenkins.logilab.org/
* https://jenkins.logilab.org/view/Cubes/
* https://jenkins.logilab.org/view/CubicWeb/
Badges
------
Badges are exported to be displayed on various pages. Here is an example :
.. raw:: html
<table><tr><td>
<a href='https://jenkins.logilab.org/job/cubicweb-default/'><img src='https://jenkins.logilab.org/buildStatus/icon?job=cubicweb-default'></a></td>
<td> is the status for the draft head on branch default of the <a href="https://hg.logilab.org/review/cubicweb">review repository</a></td></tr></table>
Adding a project to Jenkins
---------------------------
Adding a project to jenkins needs to be done through the
`jenkins-jobs project <https://hg.logilab.org/master/jenkins-jobs/file/tip/README.rst>`_.
Changes to the configuration are implemented by the
`jenkins-jobs job <https://jenkins.logilab.org/job/jenkins-jobs/>`_.