update help file

ebulk-data/help.md

@@ -31,9 +31,10 @@ argument:
 
 options:
    -d,  --directory  <path>	  Besides the dataset reference, sets the dataset directory and it links that location to the reference
+   -dd, --set-description	  Allows user to edit dataset description
    -c,  --chunk  <size>           Sets the chunk size (in megabytes) to split large files
    -s,  --storage  <storage>	  Uses the selected input storage from this set: [http, ftp, s3]
-   -cs, --custom-storage  	  Allows user to set a new input storage.
+   -cs, --custom-storage  	  Allows user to set a new input storage
    -a,  --advanced	  	  Allows to edit the Embulk cofiguration file of the input storage
    -dc, --discard-changes	  Discards local changes by checking the remote dataset