Install netcat in the dev container and make the database hostname configurable.

- build(devcontainer): Install netcat-traditional package
- feat(config): Make database hostname configurable via DB_HOST env var

.devcontainer/Dockerfile

@@ -15,6 +15,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     vim \
     net-tools \
     procps \
+    netcat-traditional \
     # Optionally add any other tools you need, e.g. vim, wget...
     && curl -sL https://deb.nodesource.com/setup_18.x | bash - \
     && apt-get install -y --no-install-recommends nodejs inotify-tools \

config/dev.exs

@@ -4,7 +4,7 @@ import Config
 config :wanderer_app, WandererApp.Repo,
   username: "postgres",
   password: "postgres",
-  hostname: "localhost",
+  hostname: System.get_env("DB_HOST", "localhost"),
   database: "wanderer_dev",
   stacktrace: true,
   show_sensitive_data_on_connection_error: true,