add n shords in json

n_shards.json

@@ -0,0 +1,14 @@
+{
+    "train": {
+        "dirty_sa": 1635,
+        "clean_sa": 767,
+        "dirty": 9900,
+        "clean": 4481
+    },
+    "test": {
+        "test": 42
+    },
+    "validation": {
+        "validation": 24
+    }
+}