docs(divider): add documentation

Author: Kamil Kisiela

README.md

@@ -72,6 +72,7 @@ Wrappers
 -	[input-container](docs/wrappers/input-container.md)
 -	[label](docs/wrappers/label.md)
 -	[messages](docs/wrappers/messages.md)
+-	[divider](docs/wrappers/divider.md)
 
 Common settings
 ---------------

docs/wrappers/divider.md

@@ -0,0 +1,14 @@
+divider
+=======
+
+md-divider
+----------
+
+### templateOptions.divider *{String}*
+
+Expects one of:
+
+-	**after** (default) - moves divider after the field or other wrappers
+-	**before** - moves divider before the field or other wrappers
+
+Make sure you use lower cases