Add a script to easily run PRs from external contributors

scripts/run-pr.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -e
+
+if [ -z "$1" ]; then
+  echo "No pull request ID was specified."
+  exit 1
+fi
+
+git fetch https://github.com/thelounge/lounge.git refs/pull/${1}/head
+git checkout FETCH_HEAD
+npm install
+npm test || true
+npm start