Add sign-artifacts.sh helper script
diff --git a/sign-artifacts.sh b/sign-artifacts.sh
new file mode 100755
index 0000000..fb4959e
--- /dev/null
+++ b/sign-artifacts.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+
+# script to generate .asc, .md5, and .sha512 files for built artifacts
+
+if [[ $# -ne 1 ]]
+then
+ echo "Usage: $0 gpg-key-id"
+ exit 1
+fi
+
+GPG_KEY="$1"
+
+cd target
+for f in apache-chainsaw-*-bin.* apache-chainsaw-*-standalone.*
+do
+ gpg --default-key="$GPG_KEY" --sign --detach-sign --armor "$f"
+ md5 "$f" >"$f.md5"
+ shasum -a 512 "$f" >"$f.sha512"
+done
