dev: add build script for relay

tools/build_relay.sh

@@ -0,0 +1,17 @@
+
+#!/bin/bash
+
+start_dir=$(pwd)
+cleanup() {
+    cd "$start_dir"
+}
+trap cleanup ERR EXIT
+set -e
+
+echo -e "\x1B[36;1m<<< Building epoxy-tls >>>\x1B[0m"
+
+cd submodules/epoxy-tls
+rustup install nightly
+rustup override set nightly
+cargo b -r
+cd -