Adds cloud_services table

This table will be used for CloudService model.

db/migrate/20160415121724_create_cloud_services.rb

@@ -0,0 +1,20 @@
+class CreateCloudServices < ActiveRecord::Migration[5.0]
+  def change
+    create_table :cloud_services do |t|
+      t.string     :ems_ref
+      t.string     :source
+      t.string     :executable_name
+      t.string     :hostname
+      t.string     :status
+      t.boolean    :scheduling_disabled
+      t.string     :scheduling_disabled_reason
+      t.bigint     :ems_id
+      t.references :host,              :type => :bigint
+      t.references :system_service,    :type => :bigint
+      t.references :availability_zone, :type => :bigint
+
+      t.timestamps
+    end
+    add_index :cloud_services, :ems_id
+  end
+end