doc: merge CodingGuidelines into CONTRIBUTING.md

Signed-off-by: Kevin Morris <kevr@0cost.org>

CONTRIBUTING.md

 # Contributing
 
-Patches should be sent to the [aur-dev@lists.archlinux.org][1] mailing list.
+Patches should be sent to the [aur-dev@lists.archlinux.org][1] mailing list
+or included in a merge request on the [aurweb repository][2].
 
 Before sending patches, you are recommended to run `flake8` and `isort`.
 
@@ -8,12 +9,20 @@ You can add a git hook to do this by installing `python-pre-commit` and running
 `pre-commit install`.
 
 [1]: https://lists.archlinux.org/listinfo/aur-dev
+[2]: https://gitlab.archlinunx.org/archlinux/aurweb
 
 ### Coding Guidelines
 
-1. All source modified or added within a patchset **must** maintain equivalent
-   or increased coverage by providing tests that use the functionality.
+DISCLAIMER: We realise the code doesn't necessarily follow all the rules.
+This is an attempt to establish a standard coding style for future
+development.
 
-2. Please keep your source within an 80 column width.
+1. All source modified or added within a patchset **must** maintain equivalent
+   or increased coverage by providing tests that use the functionality
+2. Please keep your source within an 80 column width
+3. Use four space indentation
+4. Use [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/)
+5. DRY: Don't Repeat Yourself
+6. All code should be tested for good _and_ bad cases
 
 Test patches that increase coverage in the codebase are always welcome.

doc/CodingGuidelines

-Coding Guidelines
-=================
-
-DISCLAIMER: We realise the code doesn't necessarily follow all the rules.
-This is an attempt to establish a standard coding style for future
-development.
-
-Coding style
-------------
-
-Column width: 79 columns or less within reason.
-
-Indentation: tabs (standard eight column width)
-Please don't add any mode lines. Adjust your editor to display tabs to your
-preferred width. Generally code should work with the standard eight column
-tabs.
-
-No short open tags. '<?'
-Do not end files with a close tag. '?>'
-Try embedding as little XHTML in the PHP as possible.
-Consider creating templates for XHTML.
-
-All markup should conform to XHTML 1.0 Strict requirements.
-You can use http://validator.w3.org to check the markup.
-
-Prevent PHP Notices by using isset() or empty() in conditionals that
-reference $_GET, $_POST, or $_REQUEST variables.
-
-MySQL queries should generally go into functions.
-
-Submitting patches
-------------------
-
-!!! PLEASE TEST YOUR PATCHES BEFORE SUBMITTING !!!
-Submit uncompressed git-formatted patches to aur-dev@archlinux.org.
-
-You will need to register on the mailing list before submitting:
-https://mailman.archlinux.org/mailman/listinfo/aur-dev
-
-Base your patches on the master branch as forward development is done there.
-When writing patches please keep unnecessary changes to a minimum.
-
-Try to keep your commits small and focused.
-Smaller patches are much easier to review and have a better chance of being
-pushed more quickly into the main repo. Smaller commits also makes reviewing
-the commit history and tracking down specific changes much easier.
-
-Try to make your commit messages brief but descriptive.
-
-Glossary
---------
-git-formatted patch:
-	A patch that is produced via `git format-patch` and is sent via
-	`git send-email` or as an inline attachment of an email.