Update CONTRIBUTING.md.

CONTRIBUTING.md

@@ -11,7 +11,7 @@ CHESS implements the CHESS UML/SysML profile, a specialization of the Modeling a
   * [CHESS devel Website](https://projects.eclipse.org/projects/polarsys.chess)
   * [Forum](https://www.eclipse.org/forums/index.php/f/529/)
   * Mailing list: Join our [developer list](https://accounts.eclipse.org/mailing-list/chess-dev)
-  * Bugs? [BugZilla](https://bugs.eclipse.org/bugs/enter_bug.cgi?product=Chess) is where to report them
+  * Bugs? [GitLab] (https://gitlab.eclipse.org/eclipse/chess/chess/-/issues), previous bug traking system: [BugZilla](https://bugs.eclipse.org/bugs/enter_bug.cgi?product=Chess) is where to report them
 
 ## Eclipse Contributor Agreement
 
@@ -42,7 +42,7 @@ The CHESS source code can be found [here](git://git.eclipse.org/gitroot/chess/ch
 We use Gerrit to review all changes by (non-committer) contributors before
 they are merged:
 
-https://git.eclipse.org/r/chess/chess
+https://gitlab.eclipse.org/eclipse/chess/chess.git
 
 To build the project, go to repo\org.polarsys.chess.parent\ and execute mvn -P "Eclipse-Neon-Java8" install.
 
@@ -50,10 +50,9 @@ The branch 'devel' contains the contributions that will be included in the next
 
 ### Committer contribution process
 
-1. (you) If needed, open Issue on BugZilla 
-2. (you) Create a branch from the devel branch. The branch prefix name is the ID of the issue. 
+1. (you) If needed, create the Issue on GitLab and assign it to yourself.
+2. (you) Locally, create and then push a branch starting from the devel branch. The branch prefix name is the ID of the issue. 
 3. (you) Work on it
 4. (you) Run regression tests
 5. (other committer) Review the code 
-6. (other committer) Merge new branch into devel
-7. (other committer) Update CHESS_devel update-site and bundle
+6. (other committer) To merge new branch into devel (configure and run the Jenkins process 'CHESS_merge-branch-x-to-devel').