Add mega dataset samples

samples/manifest.json

@@ -0,0 +1,33 @@
+{
+  "schema": [
+    "id",
+    "text",
+    "source",
+    "added",
+    "created",
+    "token_count",
+    "license",
+    "author"
+  ],
+  "max_rows": 32,
+  "splits": {
+    "train": {
+      "rows": 32,
+      "sources": [
+        "bcpw-public-domain"
+      ]
+    },
+    "valid": {
+      "rows": 32,
+      "sources": [
+        "bcpw-public-domain"
+      ]
+    },
+    "test": {
+      "rows": 32,
+      "sources": [
+        "bcpw-public-domain"
+      ]
+    }
+  }
+}