Adding devstack plugin support

sahara-dashboard can now be installed as a devstack plugin by
following the instructions added to the README.rst

Change-Id: I45e0353da99feb908fcd96fe4dac4d6b820f1705

README.rst

@@ -1,14 +1,22 @@
 OpenStack Dashboard plugin for Sahara project
 =============================================
 
-How to use:
------------
+How to use with Horizon on server:
+----------------------------------
 
 Use pip to install the package on the server running Horizon. Then either copy
 or link the files in sahara_dashboard/enabled to
 openstack_dashboard/local/enabled. This step will cause the Horizon service to
 pick up the Sahara plugin when it starts.
 
+How to use with devstack:
+-------------------------
+
+Add the following to your devstack ``local.conf`` file::
+
+    enable_plugin sahara-dashboard git://git.openstack.org/openstack/sahara-dashboard
+
+
 To run unit tests:
 ------------------
 

devstack/plugin.sh

@@ -0,0 +1,49 @@
+# plugin.sh - DevStack plugin.sh dispatch script sahara-dashboard
+
+SAHARA_DASH_DIR=$(cd $(dirname $BASH_SOURCE)/.. && pwd)
+
+function install_sahara_dashboard {
+    sudo pip install --upgrade ${SAHARA_DASH_DIR}
+
+    cp -a ${SAHARA_DASH_DIR}/sahara_dashboard/enabled/* ${DEST}/horizon/openstack_dashboard/enabled/
+    python ${DEST}/horizon/manage.py collectstatic --noinput
+    python ${DEST}/horizon/manage.py compress --force
+}
+
+# check for service enabled
+if is_service_enabled sahara-dashboard; then
+
+    if [[ "$1" == "stack" && "$2" == "pre-install"  ]]; then
+        # Set up system services
+        # no-op
+        :
+
+    elif [[ "$1" == "stack" && "$2" == "install"  ]]; then
+        # Perform installation of service source
+        # no-op
+        :
+
+    elif [[ "$1" == "stack" && "$2" == "post-config"  ]]; then
+        # Configure after the other layer 1 and 2 services have been configured
+        echo_summary "Installing Sahara Dashboard"
+        install_sahara_dashboard
+
+    elif [[ "$1" == "stack" && "$2" == "extra"  ]]; then
+        # Initialize and start the app-catalog-ui service
+        # no-op
+        :
+    fi
+
+    if [[ "$1" == "unstack"  ]]; then
+        # Shut down app-catalog-ui services
+        # no-op
+        :
+    fi
+
+    if [[ "$1" == "clean"  ]]; then
+        # Remove state and transient data
+        # Remember clean.sh first calls unstack.sh
+        # no-op
+        :
+    fi
+fi

devstack/settings

@@ -0,0 +1,2 @@
+# settings file for sahara-dashboard plugin
+enable_service sahara-dashboard