use rebar3 to build

Makefile

@@ -1,4 +1,4 @@
-REBAR = rebar
+REBAR = rebar3
 LASTVERSION = $(shell git rev-parse HEAD )
 
 all: compile

rebar.config

@@ -1,4 +1 @@
-{eunit_opts, [verbose]}.
 
-{cover_enabled, true}.
-{cover_print_enabled, true}.