Add README from other repo

.snapcraft/README.md

+![Rocket.Chat logo](https://rocket.chat/images/logo/logo-dark.svg?v3)
+
+# rocketchat-server snap for Ubuntu Core  (all arch)
+
+Features:
+* bundles ubuntu distribution specific and RC compatible mongodb version
+* oplog tailing for mongo by default
+* mongodb backup command  
+* mongodb restore command
+* caddy reverse proxy built-in - capable of handling free lestencrypt ssl
+
+Note:
+
+Currently, this repository is mirrored on launchpad, and used to build latest ARMHF and i386 snaps.   
+
+You can download recent builds here:
+https://code.launchpad.net/~sing-li/+snap/rocketchat-server
+
+Due an issue with the existing installed base of amd64 users (existing snap always installed mongodb 3.2  [#issue](https://github.com/RocketChat/rocketchat-server-snap/issues/3)), this snap is not currently used for amd64 builds.
+
+### Test installation 
+
+Download the latest snap file of the corresponding architecture to your Ubuntu Core 16 or 16.04LTS server.
+
+`sudo snap install ./rocketchat-server-xxxxxxxx.snap  --dangerous`
+
+
+### Development or compile your own snap
+
+Make sure you have `snapcraft` installed.
+
+```
+git clone https://github.com/RocketChat/rocketchat-server-snap
+cd rocketchat-server-snap
+snapcraft snap
+```
+
+### Regression tests (run for amd64, i386 and armhf):
+- snapcraft runs properly
+- snap installs properly
+- all services start automatically
+- rc service shows a 5-second restart delay while waiting for mongo
+	- to test manually, stop rc, stop mongo, start rc, wait 20s or so, start mongo
+- rc can be successfully restarted via the "Restart the server" button under Admin > Settings > General
+- rc service shows a 5-second delay when restarted via this button
+- all commands execute successfully:
+	- initcaddy
+		- modify the Caddyfile to test:
+			- self-signed TLS certificate (use the "tls self_signed" caddy directive)
+			- changing ports (with and without TLS)
+			- using IP address (only works without TLS)
+			- successfully acquiring a Let's Encrypt certificate (requires a registered domain)
+	- backupdb
+		- should run only with sudo
+	- restoredb
+		- ideally, stop rc service prior to running this (mongo must be running)
+		- should run only with sudo
+		- use any file outside of $snap_common (should fail)
+		- use the file created with backupdb
+		- use a dummy .tgz file without actual data
+			- with and without a "parties" directory in the archive