[doc] Add top-level README
Change-Id: Id2c578f33045abd5a474dd41984619bfa85087c3
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
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+# Eclipse GMF Runtime - Notation Metamodel
+
+The [Eclipse GMF Runtime](https://projects.eclipse.org/projects/modeling.gmf-runtime) is an industry proven application framework for creating graphical editors using Eclipse EMF and Eclipse GEF.
+
+This repository contains the EMF-based Notation metamodel which is used by GMF Runtime to store its diagrams. The the main GMF Runtime repo at https://github.com/eclipse/gmf-runtime for the actual framework code.
+
+**NOTE:** As of september of 2021, the source code for GMF Notation is now hosted on GitHub at https://github.com/eclipse/gmf-notation. If you have Git clones which refers to the old location at git.eclipse.org, update them or you will not get the latest changes.
+
+### Source
+
+* Clone: https://github.com/eclipse/gmf-notation
+
+### Issues
+
+Issues are tracked in the Eclipse Bugzilla under the _GMF-Runtime_ product:
+
+* [List of all open issues](https://bugs.eclipse.org/bugs/buglist.cgi?classification=Modeling&product=GMF-Runtime&component=Notation&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED)
+
+### Building
+
+From the top-level directory:
+
+ mvn clean verify
+
+You can build against a specific Target Platform using `-Dplatform=$PLATFORM_NAME`.
+The supported platforms are available in the `org.eclipse.gmf.runtime.target` directory.
+For example:
+
+ mvn clean verify -Dplatform=2021-06
+
+### CI
+
+The official builds are executed on the Eclipse-provided Jenkins instance at <https://ci.eclipse.org/gmf-runtime/job/gmf-notation-master/>
+
+### Update Sites
+
+Update Sites (p2 repositories) are available at:
+* <https://download.eclipse.org/modeling/gmp/gmf-notation/updates/interim>: nightly builds
+* <https://download.eclipse.org/modeling/gmp/gmf-notation/updates/milestones>: milestone builds
+* <https://download.eclipse.org/modeling/gmp/gmf-notation/updates/releases>: official releases
+
+### License
+
+[Eclipse Public License 2.0](https://www.eclipse.org/legal/epl-2.0/)
