add docker-compose.yml

- assists with starting the latest development environment built by CI
- mounts the repository at /mnt/io in the container

docker-compose.yml

+# © 2021 ETH Zurich, Mechanics and Materials Lab
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+version: "3.3"
+services:
+  dev:
+    image: registry.ethz.ch/mechanics-and-materials/ae108/dev:master
+    volumes:
+    - .:/mnt/io
+    tty: true