Update elements.rst

it's not perfect, but better than nothing.

docs/elements.rst

@@ -493,4 +493,20 @@ To be completed
 Line
 ------
 
-To be completed
+Line elements can be added to sections by using ``addLine``.
+
+.. code-block:: php
+
+    $linestyle = array('weight' => 1, 'width' => 100, 'height' => 0, 'color' => 635552);
+    $section->addLine($lineStyle)
+
+Available line style attributes:
+
+-  ``weight`` Line width in twips
+-  ``color`` Defines the color of stroke
+-  ``dash`` Line types: dash, rounddot, squaredot, dashdot, longdash, longdashdot, longdashdotdot
+-  ``beginArrow`` Start type of arrow: block, open, classic, diamond, oval
+-  ``endArrow`` End type of arrow: block, open, classic, diamond, ovel
+-  ``width`` Line-object width in pt
+-  ``height`` Line-object height in pt
+-  ``flip`` Flip the line element: true, false