Added Scalingo deployment documentation

Author: brandon-welsch

scalingo-deployment.md

@@ -0,0 +1,9 @@
+# Scalingo One Click Deployment
+
+You can quickly setup a sample Scalingo CodiMD application by clicking the button below.
+
+[![Deploy to Scalingo](https://cdn.scalingo.com/deploy/button.svg)](https://my.scalingo.com/deploy?source=https://github.com/hackmdio/codimd)
+
+If you deploy it without the button, keep in mind to use the right buildpacks. For more details, check out [`scalingo.json`](https://github.com/hackmdio/codimd/blob/master/scalingo.json) and [`.buildpacks`](https://github.com/hackmdio/codimd/blob/master/.buildpacks).
+
+###### tags: `CodiMD` `Docs`