API Plugin for Heroku Toolbelt 
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How to install this plugin
$ heroku plugins:install heroku-api-plugin
Usage
$ heroku api [--version VERSION] METHOD PATH
The api command is a convenient but low-level way to send requests
to the Heroku API. It sends an HTTP request to the Heroku API
using the given method on the given path. For methods PUT, PATCH,
and POST, it uses stdin unmodified as the request body. It prints
the response unmodified on stdout.
Method name input will be upcased, so both 'heroku api GET /apps' and
'heroku api get /apps' are valid commands.
Examples:
$ heroku api GET /apps/myapp
{ created_at: "2011-11-11T04:17:13-00:00",
id: "12345678-9abc-def0-1234-456789012345",
name: "myapp",
…
}
$ heroku api -v 3.variant /apps
# Something different
$ export HEROKU_HEADERS
$ HEROKU_HEADERS='
Content-Type: application/x-www-form-urlencoded
Accept: application/json
'
$ printf 'type=web&qty=2' | heroku api POST /apps/myapp/ps/scale
2