Add release howto

Author: andreaswolf

docs/release.md

@@ -0,0 +1,15 @@
+# Fractor release howto
+
+We use [https://github.com/symplify/monorepo-builder](symplify/monorepo-builder) for releasing new versions.
+
+## How to release a new version
+
+To release version 0.1.0, run this
+
+    vendor/bin/monorepo-builder release v0.1
+
+To release 0.1.1, run
+
+    vendor/bin/monorepo-builder release v0.1.1
+
+These commands can be tested by appending `--dry-run`