Adds CONTRIBUTING.md
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+# Contributing to Vanadium
+
+Vanadium is an open source project.
+
+It is the work of many contributors. We appreciate your help!
+
+## Filing issues
+
+We use a single GitHub repository for [tracking all
+issues](https://github.com/vanadium/issues/issues) across all Vanadium
+repositories.
+
+## Contributing code
+
+Please read the [contribution
+guidelines](https://github.com/vanadium/docs/blob/master/contributing/README.md)
+before sending patches.
+
+**We do not accept GitHub pull requests.** (We use
+[Gerrit](https://www.gerritcodereview.com/) instead for code reviews.)
+
+Unless otherwise noted, the Vanadium source files are distributed under the
+BSD-style license found in the LICENSE file.
