Adding eval metadata to Amazon Polarity (#4331)

Adding eval metadata to Amazon Polarity

Commit from https://github.com/huggingface/datasets/commit/12f92074418e36ae3c7b7287f79f98cd2b68b042

README.md

@@ -19,6 +19,55 @@ task_ids:
 - sentiment-classification
 paperswithcode_id: null
 pretty_name: Amazon Review Polarity
+train-eval-index:
+- config: amazon_polarity
+  task: text-classification
+  task_id: binary_classification
+  splits:
+    train_split: train
+    eval_split: test
+  col_mapping:
+    content: text
+    label: target
+  metrics:
+    - type: accuracy
+      name: Accuracy
+    - type: f1
+      name: F1 macro
+      args:
+        average: macro
+    - type: f1
+      name: F1 micro
+      args:
+        average: micro  
+    - type: f1
+      name: F1 weighted
+      args:
+        average: weighted
+    - type: precision
+      name: Precision macro
+      args:
+        average: macro  
+    - type: precision
+      name: Precision micro
+      args:
+        average: micro  
+    - type: precision
+      name: Precision weighted
+      args:
+        average: weighted  
+    - type: recall
+      name: Recall macro
+      args:
+        average: macro  
+    - type: recall
+      name: Recall micro
+      args:
+        average: micro  
+    - type: recall
+      name: Recall weighted
+      args:
+        average: weighted
 ---
 
 # Dataset Card for Amazon Review Polarity
@@ -157,4 +206,4 @@ Xiang Zhang, Junbo Zhao, Yann LeCun. Character-level Convolutional Networks for
 
 ### Contributions
 
-Thanks to [@hfawaz](https://github.com/hfawaz) for adding this dataset.
+Thanks to [@hfawaz](https://github.com/hfawaz) for adding this dataset.