add relay-tester scripts

scripts/relaytester-install.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+## rust must be installed
+if ! command -v "cargo" &> /dev/null; then
+    echo "rust and cargo is not installed."
+    echo "run this command to install:"
+    echo
+    echo "curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh"
+    exit
+else
+    echo "cargo is installed."
+fi
+
+rm -rf relay-tester
+git clone https://github.com/mikedilger/relay-tester.git
+cd relay-tester
+cargo build -r
+cp target/release/relay-tester $GOBIN/
+cd ..
+rm -rf relay-tester