Merge branch 'required-mixin' into 'dev'

Required-mixin doc added

See merge request documentation/doc!25

source/import_documentation/Mixins/required-mixin.rst

+.. _required-mixin:
+required-mixin
+===============
+
+The required mixin is a post-processor mixin, compatible with list-mixin.
+It provides the ability to display a list of resources according to the property/-ies its possess.
+
+Used by:
+--------
+
+    * :ref:`solid-display <solid-display>`
+
+
+Attributes
+----------
+
+``required-xyz``
+~~~~~~~~~~~~~~~~
+    The attribute takes no value. ``xyz`` represents the mandatory property of resources to be displayed.
+
+    In this example, users must have email to be dislayed.
+
+    .. code:: html
+
+        <solid-display
+            data-src=http://server/users/"
+            fields="username"
+            required-email
+        ></solid-display>
+
+    It is possible to combine this mixin twice, ``required-uvw`` and ``required-xyz``.
\ No newline at end of file

source/index.rst

@@ -57,6 +57,7 @@ Welcome to Startinblox's documentation
    import_documentation/Mixins/paginate-mixin
    import_documentation/Mixins/sorter-mixin
    import_documentation/Mixins/highlighter-mixin
+   import_documentation/Mixins/required-mixin
    import_documentation/Mixins/next-mixin
 
 .. toctree::