storage: implement postgres event query/count filter translation

config/prod.exs

@@ -1 +1,9 @@
 import Config
+
+database_url =
+  System.get_env("DATABASE_URL") ||
+    raise "environment variable DATABASE_URL is missing. Example: ecto://USER:PASS@HOST/DATABASE"
+
+config :parrhesia, Parrhesia.Repo,
+  url: database_url,
+  pool_size: String.to_integer(System.get_env("POOL_SIZE") || "10")