Google Drive is Google's file sync app that lets you store all of your files online alongside your Google Docs documents, and keep them synced with all of your devices.
Place writers' Word drafts in project folders and send review links.
Your writers' Markdown drafts become editable Word files in the right shared folders, with links and formatting problems sent back by email.
Attach review copies to ready editorial tasks and alert their editors.
Your finished Markdown draft becomes a readable review page under its project task, and you get the link in a task comment.