I figured this little trick could be useful to some of you.
In the common situation of having to hire a subcontractor to execute one task inside a big project in Redmine, you might want to give him access to just one task and leave the project otherwise untouched. There’s no way to do that directly in Redmine, but thanks to a few other concepts, this is easy to do (at least as the Redmine administrator).
Step 1, create a new user account for the guy to include.
Step 2, go to the project’s Overview tab
Step 3, click New sub-project
Step 4, give a name to the project, assign the new user as a developer for this project (as well as all users watching the task to be shared) and finish the creation of the new project
Step 5, go back to the task you wanted to share. Click the Move top-right link
Step 6, reassign the task to the new sub-project (don’t change anything more)
That’s it, you’re done.
The new sub-project contains just one task, but the contractor will have access to only that sub-project, which means it is technically shared with that user without risking confidentiality issues about the rest of the tasks!
Redmine might be written in Ruby on Rails, but it is really a great piece of software for project management!