Update SUBMITTING_PATCHES

It contained outdated information about attaching patches to bug
reports. Shorten it to the essentials.

Also format it using markdown and rename it to CONTRIBUTING.md, which is
a convention and doesn't include "patches" in the name.

Change-Id: I9ee73f16e6fa8fbf529ac0ca791e2375d4d56d68
Signed-off-by: Robin Stocker <robin@nibor.org>

CONTRIBUTING.md

@@ -0,0 +1,44 @@
+Contributing
+============
+
+Please refer to the contributor guide for all the details:
+
+https://wiki.eclipse.org/EGit/Contributor_Guide
+
+
+Reporting bugs
+--------------
+
+For anything other than small changes, it's a good idea to open a bug
+report for it (in case one doesn't already exist). This gives others the
+chance to give input and is useful for tracking. Create one here:
+
+https://bugs.eclipse.org/bugs/enter_bug.cgi?product=JGit
+
+
+Submitting changes
+------------------
+
+We use Gerrit to review all changes by committers or contributors before
+they are merged:
+
+https://git.eclipse.org/r/
+
+Make sure you have an account and have set up the `commit-msg` hook
+before committing.
+
+When committing your changes, see the contributor guide or other commits
+on what your commit message should include.
+
+Run the following to push your change for review (with `username`
+replaced by your Gerrit username):
+
+    git push ssh://username@git.eclipse.org:29418/jgit/jgit.git HEAD:refs/for/master
+
+Add the link to the review as a comment on the bug report, so that
+people coming from the bug report can find it.
+
+Then wait for someone to review your change. If there is something to be
+corrected, amend your commit and push it again.
+
+Have fun :).

SUBMITTING_PATCHES

@@ -1,106 +0,0 @@
-Short Version:
-
- - Make small logical changes.
- - Provide a meaningful commit message.
-
- - Review and follow the Eclipse Due Diligence Process
-
-     http://www.eclipse.org/projects/dev_process/ip-process-in-cartoons.php
-     http://www.eclipse.org/legal/EclipseLegalProcessPoster.pdf
-
- - Review and follow the current guidelines:
-
-     http://wiki.eclipse.org/EGit/Contributor_Guide
-
-
-Long Version:
-
-I wanted a file describing how to submit patches for JGit,
-so I started with the one found in the core Git distribution
-(Documentation/SubmittingPatches), which itself was based on the
-patch submission guidelines for the Linux kernel.
-
-However there are quite a few differences, so please review and
-familiarize yourself with the following relevant bits:
-
-
-(1) Make separate commits for logically separate changes.
-
-Unless your patch is really trivial, you should not be sending
-out a patch that was generated between your working tree and your
-commit head.  Instead, always make a commit with complete commit
-message and generate a series of patches from your repository.
-It is a good discipline.
-
-Describe the technical detail of the change(s).
-
-If your description starts to get too long, that's a sign that you
-probably need to split up your commit to finer grained pieces.
-
-I am very picky about formatting.  Make sure your final version
-of every file was formatted using the Eclipse code formatter
-using the project specific settings (Properties->Java Code
-Style->Formatter->"Java Conventions [built-in]").
-
-
-(2) Generate your patch using git tools out of your commits.
-
-git based diff tools (git, and StGIT included) generate unidiff,
-which is the only acceptable format.
-
-You do not have to be afraid to use -M option to "git diff" or "git
-format-patch", if your patch involves file renames.  The receiving
-end can handle them just fine.
-
-Please make sure your patch does not include any extra files which
-do not belong in a patch submission.  Make sure to review your
-patch after generating it, to ensure accuracy.  Before sending out,
-please make sure it cleanly applies to the "master" branch head.
-
-
-(3) Check the license.
-
-JGit is licensed under the Eclipse Distribution License (EDL,
-http://www.eclipse.org/org/documents/edl-v10.html), which is a
-renamed version of the new style/3-clause BSD license.
-
-Under this licensing model *every* file within the project
-*must* list which license covers it in the header of the file.
-Any new contributions to an existing file *must* be submitted under
-the current license of that file.  Any new files *must* clearly
-indicate which license they are provided under in the file header.
-
-Please verify that you are legally allowed and willing to submit your
-changes under the license covering each file *prior* to submitting
-your patch.  It is virtually impossible to remove a patch once it
-has been applied and pushed out.
-
-
-(4) Review the Eclipse Due Diligence Process.
-
-  http://www.eclipse.org/legal/EclipseLegalProcessPoster.pdf
-
-
-(5) Sending your patches.
-
-"git format-patch" command follows the best current practice to
-format a commit as a reviewable text message.
-
-At the beginning of the patch should come your commit message,
-a line that consists of three dashes, followed by the diffstat
-information and the patch itself.  If you are forwarding a patch
-from somebody else, optionally, at the beginning of the e-mail
-message just before the commit message starts, you can put a "From:
-" line to name that person.
-
-You often want to add additional explanation about the patch,
-other than the commit message itself.  Place such "cover letter"
-material between the three dash lines and the diffstat, or please
-place it in the bug description itself.
-
-Open a new bug on the Eclipse bug tracker on the EGit project:
-
-  https://bugs.eclipse.org/bugs/enter_bug.cgi?product=EGit
-
-Attach the mailbox file(s) created by "git format-patch" to the bug.
-