Add Alpha label

Works exactly the same as the beta label. 
For this ticket:
https://trello.com/c/0eHTxG4j/141-add-alpha-label-to-eim-manual
They're guidelines not rules, but I would add spaces: 
`Use spaces around operators, after commas, colons and semicolons, around { and before }.`
https://github.com/alphagov/styleguides/blob/master/ruby.md#general