Moved Ubuntu packaging scripts and deb repo to special branches

In pull requests #307 and #308, I'm adding the packaging scripts and deb repo to special branches.
#307
#308

README.md

@@ -13,16 +13,20 @@ See https://github.com/facebook/mcrouter/wiki to get started.
 
 ### New! Ubuntu package available
 
-Currently, we only have Ubuntu Xenial (16.04) amd64 package.
+Currently, we support Ubuntu Xenial (16.04) and Bionic (18.04) amd64.
 Here is how to install it:
 
 Add the repo key:
 
-    $ wget -O - https://facebook.github.io/mcrouter/debian/PUBLIC.KEY | sudo apt-key add
+    $ wget -O - https://facebook.github.io/mcrouter/debrepo/xenial/PUBLIC.KEY | sudo apt-key add
 
-Add the following line to apt sources file /etc/apt/sources.list
+For Xenial: add the following line to apt sources file /etc/apt/sources.list
 
-    deb https://facebook.github.io/mcrouter/debian xenial contrib
+    deb https://facebook.github.io/mcrouter/debrepo/xenial xenial contrib
+
+For Bionic: add the following line to apt sources file /etc/apt/sources.list
+
+    deb https://facebook.github.io/mcrouter/debrepo/bionic bionic contrib
 
 Update the local repo cache: