Migration docker image

any idea on how to execute migration with cli migration ?

i'm using 

```
FROM hasura/graphql-engine:v1.3.0.cli-migrations-v2

ENV HASURA_GRAPHQL_ENABLE_TELEMETRY false

COPY ./migrations /hasura-migrations
COPY ./metadata /hasura-metadata

CMD graphql-engine serve --server-port $PORT
```

it seems render.com skip the migration, all files are copied but no migration executed