Add the install instructions for the snap (#4843)

README.md

@@ -53,6 +53,15 @@ chmod +x minio
 ./minio server ~/Photos
 ```
 
+### Snap
+You can install the latest `minio` [snap](https://snapcraft.io), and help testing the most recent changes of the master branch in [all the supported Linux distros](https://snapcraft.io/docs/core/install) with:
+
+```sh
+sudo snap install minio --edge
+```
+
+Every time a new version of `minio` is pushed to the store, you will get it updated automatically.
+
 ## Microsoft Windows
 ### Binary Download
 | Platform| Architecture | URL|