storage.md in fog-azure-rm-0.2.0

- old
+ new

@@ -57,10 +57,16 @@
 
 ```ruby
 azure_storage_service.storage_accounts.check_name_availability('<Storage Account name>')
 ```
 
+## Check Storage Account Existence
+
+```ruby
+azure_storage_service.storage_accounts.check_storage_account_exists(<Resource Group name>, <StorageAccountName>)
+```
+
 ## Create Storage Account
 
 Create a new storage account. Replication attribute for Standard and Premium account types are as follows 
 
 Standard: LRS (Standard Locally-redundant storage)
@@ -157,9 +163,15 @@
 Delete a Disk from a storage account. Disk must be in unlocked state i.e detached from server(virtual machine) to successfully perform this action.
 By default the disk will be deleted from the container 'vhds'. You can specify other container by set options[:container_name].
 
 ```ruby
 azure_storage_service.delete_disk('<Data Disk Name>', options = {})
+```
+
+## Check Storage Container Existence
+
+```ruby
+azure_storage_service.directories.check_container_exists(<container name>)
 ```
 
 ## Create a storage container
 
 Create a storage container in the current storage account.