Detailed merge request instructions for Gitorious.

Most Gitorious users know this procedure, but it seems useful to
document it in great detail here, since copyleft.org seeks contributions
from those who might be knew to Git, and those who are more familiar
with procedures of other collaboration sites.

CONTRIBUTING.md

@@ -86,3 +86,90 @@ are not necessarily rejected.  In fact, if your change is a fix for typo,
 spelling, grammar, formatting or anything urgent, submitting a patch against
 'master' may make more sense.
 
+### Contributing via Gitorious
+
+First-time contributors may want to do the following four items first:
+
+0. [Create an account on Gitorious](https://gitorious.org/users/new)
+
+1. [Visit gitorious.org/copyleft-org/tutorial](https://gitorious.org/copyleft-org/tutorial)
+    and click "Clone".
+
+    Instead of the default, you might call your clone
+    "MYNAME-copyleft-tutorial-suggestions".
+
+2. On the command line create a *local* clone of your Clone, by typing:
+
+        $ git clone git@gitorious.org:copyleft-org/MYNAME-copyleft-tutorial-suggestions.git copyleft-tutorial
+        $ cd copyleft-tutorial
+        $ git remote rename origin MYNAME-copyleft-tutorial-suggestions
+
+    (The last part isn't strictly necessary; you just might want to name the
+    upstream repository a more descriptive name, since below you'll add the
+    official repository as well).
+
+3. Now, add to your clone a copy of the "real" Conservancy policies
+   repository, and make a branch that tracks the official version:
+
+        $ git remote add copyleft-tutorial-official git@gitorious.org:copyleft-org/tutorial.git
+        $ git fetch copyleft-tutorial-official
+        $ git branch --track official-master copyleft-tutorial-official/master
+        $ git branch --track official-next copyleft-tutorial-official/next
+
+That completes the first-time setup.  Next is a workflow each proposed merge
+request.
+
+0. First, ensure the Git repository points at the right branch and all old
+   changes are committed.
+
+        $ git checkout official-next
+        $ git pull copyleft-tutorial-official
+        $ git status
+
+   The output of the last command should look like this:
+
+        # On branch official-next
+        nothing to commit (working directory clean)
+
+   If you don't get that output, you probably have uncommitted changes, which
+   is beyond the scope of this tutorial.
+
+1. Next, create a new branch to hold your changes:
+
+        $ git checkout -b my-new-idea-for-tutorial official-next
+
+   Use a name that briefly describes your planned proposal for
+   "my-new-idea-for-tutorial".
+
+2. Make your edits.  If you're editing the tutorial, you likely want to focus
+   on the files ending in '.tex'.  Commit frequently while you're editing
+   with:
+
+        $ git commit -a
+
+   Write useful and clear commit messages that explain the purpose of the
+   changes.
+
+3. When you are done all the changes related to 'my-new-idea-for-tutorial',
+   verify they've all been committed this way:
+
+        $ git status
+        # On branch my-new-idea-for-tutorial
+        nothing to commit (working directory clean)
+
+4. Next, upload and publish those ideas to your own clone on Gitorious.
+
+        $ git push MYNAME-copyleft-tutorial-suggestions my-new-idea-for-tutorial
+
+    That's the end of the command-line part.
+
+5. Now, visit Gitorious' merge-requst creation web interface at
+   https://gitorious.org/copyleft-org/MYNAME-copyleft-tutorial-suggestions/merge_requests/new
+   Initiate your merge request with by setting:
+
+        Summary:       Briefly describe your proposal
+        Description:   More completely describe your proposal
+        Target:        tutorial
+        Target Branch: next
+        Source Branch: my-new-idea-for-tutorial
+