add replica set init

docker/prod/mongo/init/init_replica_set.js

@@ -0,0 +1,15 @@
+try {
+  const status = rs.status();
+  printjson(status);
+} catch (e) {
+  if (e.codeName === "NotYetInitialized") {
+    print("Replica set not initialized. Initiating...");
+    rs.initiate({
+      _id: "rs0",
+      members: [{ _id: 0, host: "mongodb:27017" }],
+    });
+  } else {
+    print("Unexpected error during rs.status():");
+    printjson(e);
+  }
+}