create_card_from_excel: Create a new card on a specified 'Upwave' board
In upwaver: Access 'Upwave' API

create_card_from_excel() adds a new card in the most-left column of the given board. The Information of the card are taken from an excel file.

1 2	create_card_from_excel(excel_file, sheet, line_number, organisation, board_id, board_name, token)

`excel_file`	A character. The path to an excel-file providing informations for user-stories; expected columns: US-ID, name, description
`sheet`	An integer or a character. The sheet of the excel-file providing informations for user-stories; expected columns: US-ID, name, description
`line_number`	An integer. The line number in the spreadsheet starting from 1
`organisation`	A character. The name of the organisation as specified in the URL: https://<organisation>.upwave.io
`board_id`	An integer. The board number, the card has to be created in
`board_name`	A character. The board name, the card has to be created in
`token`	A character. The API token to access boards on upwave.io. The token can be obtained by visiting your account settings. Click your profile image, select "Settings" and find your API-Key in the "Account" tab.

## Not run: create_card_from_excel(excel_file = "path_to_your_excel_file", sheet = (sheetno. or sheetname),
line_number = linenr, organisation = "your_organisation", board_id = your_board_id,
board_name = "your_board_name", "token = your_api_token")
## End(Not run)