Add Supplemental Developer Contribution Guidelines

Signed-off-by: Xue Mingdi <[email protected]>

CONTRIBUTING.md

@@ -80,7 +80,7 @@ get going:
     git add add-this-doc.md
     git commit -s -m "Added a shiny new doc."
     ```
-
+    For more details, please refer to [DCO](docs/developer/Supplemental_developer_guide.md#DCO)
 11. Push from your branch (for example, `doc-updates`) to **the relevant branch
   on your fork on GitHub:**
 

docs/developer/Supplemental_developer_guide.md

@@ -0,0 +1,87 @@
+---
+title: Supplementary Developer Contribution Guidelines
+sidebar_position: 8
+---
+
+# Supplementary Developer Contribution Guidelines:
+
+
+## DCO
+
+
+DCO (Developer Certificate of Origin) needed for each commit, contributors must sign off on their commits to certify that they have the right
+to submit the code they are contributing. This is done using `--signoff` option in Git.  
+
+The sign-off is a simple line at the end of the commit message, which looks like this:  
+
+```
+    Signed-off-by: Your Name <[email protected]>
+```
+
+You can add this automatically to your commit message using the `-s` or `--signoff` 
+
+flag when you make a commit,here are the steps to follow so the computer can add it for you:
+
+**Set your legal name in the git configuration:**
+
+```
+    git config user.name "Legal Name" 
+```
+
+**Set your email in the git configuration:**
+
+```
+    git config user.email "[email protected]" 
+```
+
+**Add the -s  or --signoff  to all git commit  invocations.**
+
+```
+    git commit -s -m "Your commit message"
+```
+
+**Add above signoff line for last unsigned commit**
+
+```
+    git commit -s --amend
+```
+
+
+## Ensuring to squash similiar commits
+
+
+To ensure that your pull request does not contain multiple similiar commits, you may need to squash your commits.
+
+Here's how to do it:
+
+**Rebase Your Branch:**
+
+Rebase your feature branch onto the latest version of the target branch
+
+```
+    git checkout feature-branch
+    git fetch origin
+    git rebase origin/master
+```
+
+**Squash Commits:**
+
+Interactive rebase to squash commits:
+
+```
+    git rebase -i HEAD~N
+```
+
+Replace 'N' with the number of similiar commits you want to squash. In the interactive rebase interface, 
+
+Replace 'pick' with 'squash' for all commits except the first one. And amend the commit message if needed.
+
+**Force Push:**
+
+After squashing your commits, force push your branch to update your pull request:
+
+```
+    git push -f 
+```
+
+