Feat: Logging + Metrics

[Nelson]

This is "on hold" ... pending dwyl/logs#1

At present the imgup app has no DB 💭
So we have zero insight into what images are being uploaded. 🙈 🤷‍♂️
This is "OK" for a basic demo...
But it's not great for a "production" app where we want to track metrics. 📈
We need to "productionize"! 🚀

Todo

• Define the DB schema for storing anon logging data.
  We can borrow (or draw inspiration) from: dwyl/auth/lib/auth/log.ex
  • user_agent table should mimmic the one in auth: lib/auth/user_agent.ex so that we store the relevant detail. The other field we could add is
• Create the necessary migrations for the schema we define.
• Create a simple interface that logs required events ...