Merge branch 'use-couch-rand-module'

Fixes #6
diff --git a/src/ioq.erl b/src/ioq.erl
index 93377d6..9ca2656 100644
--- a/src/ioq.erl
+++ b/src/ioq.erl
@@ -136,7 +136,7 @@
         {false, true} ->
             choose_next_request(#state.compaction, State);
         {false, false} ->
-            case random:uniform() < State#state.ratio of
+            case couch_rand:uniform() < State#state.ratio of
                 true ->
                     choose_next_request(#state.compaction, State);
                 false ->