clarify my DCO-like stance, and provide cloning info

CONTRIBUTING.md

@@ -1,7 +1,10 @@
 # How to Contribute
 
 incorporeal-cms is a personal project seeking to implement a simpler, cleaner form of what would
-commonly be called a "CMS". I appreciate any help in making incorporeal-cms better.
+commonly be called a "CMS". I appreciate any help in making it better.
+
+incorporeal-cms is made available under the GNU Affero General Public License version 3, or any
+later version.
 
 ## Opening Issues
 
@@ -10,8 +13,24 @@ Issues should be posted to my Gitea instance at
 recommend starting the title with "Improvement:", "Bug:", or similar, so I can do a high level of
 prioritization.
 
-## Guidelines for Patches, etc.
+## Contributions
+
+I don't expect contributors to sign up for my personal Gitea in order to send contributions, but it
+of course makes it easier. If you wish to go this route, please sign up at
+<https://git.incorporeal.org/bss/incorporeal-cms> and fork the project. People planning on
+contributing often are also welcome to request access to the project directly.
+
+Otherwise, contact me via any means you know to reach me at, or <bss@incorporeal.org>, to discuss
+your change and to tell me how to pull your changes.
 
+### Guidelines for Patches, etc.
+
+* Cloning
+    * Clone the project. I would advise using a pull-based workflow where I have access to the hosted
+      repository --- using my Gitea, cloning to a public GitHub, etc. --- rather than doing this over
+      email, but that works too if we must.
+    * Make your contributions in a new branch, generally off of `master`.
+    * Send me a pull request when you're ready, and we'll go through a code review.
 * Code:
     * Keep in mind that I strive for simplicity in the software. It serves files and renders
       Markdown, that's pretty much it. Features around that function are good; otherwise, I need
@@ -27,22 +46,31 @@ prioritization.
     * Squash tiny commits if you'd like. I prefer commits that make one atomic conceptual change
       that doesn't affect the rest of the code, assembling multiple of those commits into larger
       changes.
-    * Follow something like [Chris Beams'](https://chris.beams.io/posts/git-commit/) post on
+    * Follow something like [Chris Beams's post](https://chris.beams.io/posts/git-commit/) on
       formatting a good commit message.
+    * Please make sure your Author contact information is stable, in case I need to reach you.
+    * Consider cryptographically signing (`git commit -S`) your commits.
 
-## Contributions
+### Custody of Contributions
 
-I don't expect contributors to sign up for my personal Gitea in order to send contributions, but it
-of course makes it easier. If you wish to go this route, please sign up at
-<https://git.incorporeal.org/bss/incorporeal-cms> and fork the project. People planning on
-contributing often are also welcome to request access to the project directly.
+I do not request the copyright of contributions be assigned to me or to the project, and I require no
+provision that I be allowed to relicense your contributions. My personal oath is to maintain
+inbound=outbound in my open source projects, and the expectation is authors are responsible for their
+contributions.
 
-Otherwise, contact me via any means you know to reach me at, or <bss@incorporeal.org>, to discuss
-your change and to tell me how to pull your changes.
+I am following the *spirit* of the [Developer Certificate of Origin](https://developercertificate.org/),
+but in a simplified fashion:
+
+By making a contribution to this project, you certify that:
 
-### Copyright of Contributions
+1. The contribution was created by you and you have the right to submit it under the open source license
+   indicated in the LICENSE file; or
+2. The contribution is based upon previous work that is covered under an appropriate open source license
+   compatible with the license indicated in the LICENSE file, and you have the right to contribute that
+   work with or without modifications, under the terms of that same open source license; or
+3. The contribution was provided directly to you by some other person who certified points 1, 2, or 3, and
+   you have not modified it.
 
-Accepted changes remain the copyright of the original author, but please include appropriate contact
-methods in the event I choose to provide the project under a new license and need to contact you
-to approve the new license terms. Please note that the software is provided under the GNU AGPLv3 (or
-later).
+In the event of point 3, your commit **must** include the Signed-off-by line(s) as a chain of custody,
+via `git commit -s`. For points 1 and 2, your commit with accurate Author information doubles as direct
+custody.