Nice! I could get it exported => app.json · GitHub
Sure they are 
, I had to create manually the directory middleware/bundles but once directory exists, plugins are downloaded correctly and stored there
docker exec tykquickstart_tyk_gateway_1 ls -la middleware/bundles
total 12
drwxr-xr-x 3 root root 4096 May 19 07:55 .
drwxr-xr-x 5 root root 4096 May 19 07:55 ..
drwxr-xr-x 3 root root 4096 May 19 07:55 1c608d6ba38943996311271c37e8c6fc-auth-bundle-536.zip