feat(Grafana): Add postgres configuration

grafana/docker-compose.postgres.yml

@@ -0,0 +1,11 @@
+version: "3.8"
+
+services:
+  grafana:
+    environment:
+      # https://grafana.com/docs/grafana/latest/administration/configuration/#database
+      GF_DATABASE_TYPE: postgres
+      GF_DATABASE_HOST: postgres # Name is same as ../postgres/docker-compose.yml:8
+      GF_DATABASE_NAME: ${POSTGRES_DB:?err}
+      GF_DATABASE_USER: ${POSTGRES_USER:?err}
+      GF_DATABASE_PASSWORD: ${POSTGRES_PASSWORD:?err}