Update shard index (added shard 0)

shard_index.json

@@ -0,0 +1,11 @@
+{
+  "shards": {
+    "0": {
+      "shard_id": 0,
+      "total_shards": 22,
+      "num_sequences": 1015836,
+      "block_size": 1024
+    }
+  },
+  "total_shards": 22
+}