doc: Explain what a query resource is

Fixes #693

doc/manuals/datamodel/search.rst

@@ -204,10 +204,12 @@ Query-model arguments
 
 **query_id**
 
-  Load the query arguments from the saved ``query`` resource.
+  Load the query arguments from the saved ``query`` resource. 
 
   ``query_id=331``
 
+  .. seealso:: :ref:`manual-query-resources`
+
 **publication_month**
 
   Filter on month of publication date
@@ -253,3 +255,22 @@ is the ``cat=`` filter: if you specify multiple categories, those
 categories are "OR"'ed together, to allow to search in multiple
 distinct categories with a single search query.
 
+
+
+.. _manual-query-resources:
+
+Query resources
+---------------
+
+Query resources are, as the name implies,
+:ref:`manual-datamodel-resources` of the special category `query`. In
+the admin this category is called "search query". it is basically a
+stored (and thus content manageable) search query. You create an
+editable search query in an admin page that then is invoked from a
+template.
+
+When creating such a resource in the page, you will see on the admin
+edit page an extra text field in which you can add search terms. Each
+search term goes on its own line, and the possible search terms are
+equal to the ones described on this page (the `Query-model
+arguments`).