avoid npm install error within a broken git submodule

docker-compose.yml

@@ -92,7 +92,9 @@ services:
     network_mode: host
   
   webrtc-sfu:
-    build: ./bbb-webrtc-sfu
+    build: 
+      context: ./bbb-webrtc-sfu
+      dockerfile: mod/webrtc-sfu/Dockerfile
     depends_on:
       - redis
       - kurento

mod/webrtc-sfu/Dockerfile

@@ -0,0 +1,21 @@
+FROM node:12
+
+ADD . app
+
+WORKDIR app
+
+ENV NODE_ENV production
+
+
+# due to the git submodule npm install crashes with following error:
+# npm ERR! fatal: Not a git repository: ../.git/modules/bbb-webrtc-sfu
+# we simply delete the .git file
+RUN cp config/default.example.yml config/production.yml \
+ && rm .git \
+ && npm install --unsafe-perm \
+ && npm cache clear --force
+
+EXPOSE 3008
+
+ENTRYPOINT [ "./docker-entrypoint.sh" ]
+CMD [ "npm", "start" ]