From http://simplicitybliss.com/2013/08/reviewing-documents-with-omnifocus-and-hazel/

new_gist_file

tell application "Finder" to set file_name to (name of theFile)

    tell application "OmniFocus"
    set task_title to "Review " & file_name
    tell default document
        set newTask to make new inbox task with properties {name:task_title}
        tell the note of newTask
            make new file attachment with properties {file name:theFile,    embedded:false}
        end tell
    end tell
end tell