CONTRIBUTING: Document our expectation of DCO

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
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@@ -78,6 +78,16 @@ get there in the best possible way. You should tell the story of
 flying by plane to get somewhere, not how you explored the world and
 eventually invented flying machines to travel faster.
 
+**Sign off your commits:** The commits in a merge request must each
+individually carry a `Signed-off-by` footer.  This footer should
+identify the entity which has checked the commit and confirmed that
+it is acceptable for it to be contributed to the Subplot project.
+
+The Subplot project requires that each contribution to it meets
+the assertions listed in the Developer Certificate of Origin version
+1.1 (the text of which can be found in `DCO-1-1.txt` alongside this
+document).
+
 # Definition of done
 
 When a change is made to Subplot, it must meet the following minimum