add what is behind sib server

source/import_documentation/install-sib-server.rst

 How to install a SIB server
 ############################
 
+What is behind SiB server ?
+==========================
+Our solution is based on `Django <https://www.djangoproject.com/>`__ and named `DjangoLDP <https://git.startinblox.com/djangoldp-packages/djangoldp/>`__, adapted to be compatible with Linked Datas convention.
+
+Go to `Server Architecture`_ to know more about it.
+
+
 Requirements
 ============