add etldoc to layer_highway_name

gen_etl_graph_highway_name.sh

@@ -0,0 +1,19 @@
+
+
+DOT=highway_name.dot
+
+echo "digraph G
+{    
+rankdir=LR;
+" > $DOT
+
+cat ./layers/highway_name/layer.sql          | grep "\-\- etldoc:" |  sed 's/-- etldoc://g' >>$DOT
+cat ./layers/highway_name/merge_highways.sql | grep "\-\- etldoc:" |  sed 's/-- etldoc://g' >>$DOT 
+
+echo "
+}
+" >> $DOT
+
+cat $DOT
+
+dot -Tpng $DOT > layer_highway_names_etl.png