Switch application base to alpine, remove expose of database port, re…

[Danpiel]

Hello @synzen, made couple fixes to the setup, here is the list

• Added restart policies to both containers, the endless restart loop due to some error in configuration can drain Discord API limits and result bot ban, limiting to 5 restarts for mongodb and 10 restarts for application
• Removed ports which bind port to host, and added expose of mongodb port to linked application, so database is accessible only from application. To make a direct access to mongodb can add

ports:
- random_host_port:27017

and use your preferred port without application and database reconfiguration

• Explicit set of version and images from mongodb and node, also node is set to alpine, which uses less space
• Removed - (dash) in service definition, this can cause issues between docker-compose versions, due to different name handling

[synzen]

Excellent to have input from somewhere to has had more than 1 day of experience with Docker! Works perfectly, but only after I put change

expose: 27017

to

expose:
  - 27017

I'm assuming you forgot to give it a new line?