added support local mirrors

Change-Id: I542dbf1b04b2e7569522896506a3a46fe8f8b200
diff --git a/README.rst b/README.rst
index 178b0c9..ff25578 100644
--- a/README.rst
+++ b/README.rst
@@ -149,6 +149,50 @@
         - 'ssh-rsa ASDFOSADFISdfasdfasjdklfjasdJFASDJfASdf923@AAAAB3NzaC1yc2EAAAADAQABAAACAQCv8ISOESGgYUOycYw1SAs/SfHTqtSCTephD/7o2+mEZO53xN98sChiFscFaPA2ZSMoZbJ6MQLKcWKMK2OaTdNSAvn4UE4T6VP0ccdumHDNRwO3f6LptvXr9NR5Wocz2KAgptk+uaA8ytM0Aj9NT0UlfjAXkKnoKyNq6yG+lx4HpwolVaFSlqRXf/iuHpCrspv/u1NW7ReMElJoXv+0zZ7Ow0ZylISdYkaqbV8QatCb17v1+xX03xLsZigfugce/8CDsibSYvJv+Hli5CCBsKgfFqLy4R5vGxiLSVzG/asdjalskjdlkasjdasd/asdajsdkjalaksdjfasd/fa/sdf/asd/fas/dfsadf blah@blah'
 
 
+Usage of local repos
+
+.. code-block:: yaml
+  maas:
+    cluster:
+      enabled: true
+      region:
+        port: 80
+        host: localhost
+      saltstack_repo_key: |
+        -----BEGIN PGP PUBLIC KEY BLOCK-----
+        Version: GnuPG v2
+
+        mQENBFOpvpgBCADkP656H41i8fpplEEB8IeLhugyC2rTEwwSclb8tQNYtUiGdna9
+        m38kb0OS2DDrEdtdQb2hWCnswxaAkUunb2qq18vd3dBvlnI+C4/xu5ksZZkRj+fW
+        tArNR18V+2jkwcG26m8AxIrT+m4M6/bgnSfHTBtT5adNfVcTHqiT1JtCbQcXmwVw
+        WbqS6v/LhcsBE//SHne4uBCK/GHxZHhQ5jz5h+3vWeV4gvxS3Xu6v1IlIpLDwUts
+        kT1DumfynYnnZmWTGc6SYyIFXTPJLtnoWDb9OBdWgZxXfHEcBsKGha+bXO+m2tHA
+        gNneN9i5f8oNxo5njrL8jkCckOpNpng18BKXABEBAAG0MlNhbHRTdGFjayBQYWNr
+        YWdpbmcgVGVhbSA8cGFja2FnaW5nQHNhbHRzdGFjay5jb20+iQE4BBMBAgAiBQJT
+        qb6YAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAOCKFJ3le/vhkqB/0Q
+        WzELZf4d87WApzolLG+zpsJKtt/ueXL1W1KA7JILhXB1uyvVORt8uA9FjmE083o1
+        yE66wCya7V8hjNn2lkLXboOUd1UTErlRg1GYbIt++VPscTxHxwpjDGxDB1/fiX2o
+        nK5SEpuj4IeIPJVE/uLNAwZyfX8DArLVJ5h8lknwiHlQLGlnOu9ulEAejwAKt9CU
+        4oYTszYM4xrbtjB/fR+mPnYh2fBoQO4d/NQiejIEyd9IEEMd/03AJQBuMux62tjA
+        /NwvQ9eqNgLw9NisFNHRWtP4jhAOsshv1WW+zPzu3ozoO+lLHixUIz7fqRk38q8Q
+        9oNR31KvrkSNrFbA3D89uQENBFOpvpgBCADJ79iH10AfAfpTBEQwa6vzUI3Eltqb
+        9aZ0xbZV8V/8pnuU7rqM7Z+nJgldibFk4gFG2bHCG1C5aEH/FmcOMvTKDhJSFQUx
+        uhgxttMArXm2c22OSy1hpsnVG68G32Nag/QFEJ++3hNnbyGZpHnPiYgej3FrerQJ
+        zv456wIsxRDMvJ1NZQB3twoCqwapC6FJE2hukSdWB5yCYpWlZJXBKzlYz/gwD/Fr
+        GL578WrLhKw3UvnJmlpqQaDKwmV2s7MsoZogC6wkHE92kGPG2GmoRD3ALjmCvN1E
+        PsIsQGnwpcXsRpYVCoW7e2nW4wUf7IkFZ94yOCmUq6WreWI4NggRcFC5ABEBAAGJ
+        AR8EGAECAAkFAlOpvpgCGwwACgkQDgihSd5Xv74/NggA08kEdBkiWWwJZUZEy7cK
+        WWcgjnRuOHd4rPeT+vQbOWGu6x4bxuVf9aTiYkf7ZjVF2lPn97EXOEGFWPZeZbH4
+        vdRFH9jMtP+rrLt6+3c9j0M8SIJYwBL1+CNpEC/BuHj/Ra/cmnG5ZNhYebm76h5f
+        T9iPW9fFww36FzFka4VPlvA4oB7ebBtquFg3sdQNU/MmTVV4jPFWXxh4oRDDR+8N
+        1bcPnbB11b5ary99F/mqr7RgQ+YFF0uKRE3SKa7a+6cIuHEZ7Za+zhPaQlzAOZlx
+        fuBmScum8uQTrEF5+Um5zkwC7EXTdH1co/+/V/fpOtxIg4XO4kcugZefVm5ERfVS
+        MA==
+        =dtMN
+        -----END PGP PUBLIC KEY BLOCK-----
+      saltstack_repo_xenial: "http://${_param:local_repo_url}/ubuntu-xenial stable salt"
+      saltstack_repo_trusty: "http://${_param:local_repo_url}/ubuntu-trusty stable salt"
+
 Single MAAS cluster service [multiple racks]
 
 .. code-block:: yaml