add missing md file

Author: benoitc

doc/hackney_metrics.md

@@ -0,0 +1,30 @@
+
+
+# Module hackney_metrics #
+* [Function Index](#index)
+* [Function Details](#functions)
+
+<a name="index"></a>
+
+## Function Index ##
+
+
+<table width="100%" border="1" cellspacing="0" cellpadding="2" summary="function index"><tr><td valign="top"><a href="#get_engine-0">get_engine/0</a></td><td></td></tr><tr><td valign="top"><a href="#init-0">init/0</a></td><td></td></tr></table>
+
+
+<a name="functions"></a>
+
+## Function Details ##
+
+<a name="get_engine-0"></a>
+
+### get_engine/0 ###
+
+`get_engine() -> any()`
+
+<a name="init-0"></a>
+
+### init/0 ###
+
+`init() -> any()`
+