Add example .env file

packages/explorer-message-bus-api/.env.example

@@ -0,0 +1,16 @@
+# Change to "deploy" once 2024 events are synced
+# START_DATE=deploy
+START_DATE=2024-01-01
+
+# DFK
+PONDER_RPC_URL_53935=https://subnets.avax.network/defi-kingdoms/dfk-chain/rpc
+
+# Harmony
+PONDER_RPC_URL_1666600000=https://api.s0.t.hmny.io
+
+# Klaytn
+# Helpful: https://docs.blockpi.io/documentations/pricing-and-rate-limit
+PONDER_RPC_URL_8217=https://klaytn.blockpi.network/v1/rpc/public
+
+# (Optional) Postgres database URL. If not provided, SQLite will be used.
+DATABASE_URL=