add release script

release.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+# Creates a tagged version. Releases must be manually created.
+
+if [ $# -ne 1 ]; then
+  echo "Usage: $0 \"<release message>\""
+  exit 1
+fi
+
+raw_version=$(grep -E 'modVersion(\s*)=(\s*)' "./gradle.properties" | cut -d'=' -f2 | tr -d ' ')
+branch_name=$(grep -E 'branchName(\s*)=(\s*)' "./gradle.properties" | cut -d'=' -f2 | tr -d ' ')
+
+version="$raw_version+$branch_name"
+
+echo "Creating tag for version $version with message '$1'"
+
+git tag -s -a v"$version" -m "$1"
+
+git push origin v"$version"