added fashion-mnist to docs (#327)

Author: kashif

docs/source/datasets.rst

@@ -30,6 +30,11 @@ MNIST
 
 .. autoclass:: MNIST
 
+Fashion-MNIST
+~~~~~~~~~~~~~
+
+.. autoclass:: FashionMNIST
+
 COCO
 ~~~~
 

torchvision/datasets/mnist.py

@@ -140,7 +140,20 @@ def download(self):
 
 
 class FashionMNIST(MNIST):
-    """`Fashion MNIST <https://github.com/zalandoresearch/fashion-mnist>`_ Dataset.
+    """`Fashion-MNIST <https://github.com/zalandoresearch/fashion-mnist>`_ Dataset.
+
+    Args:
+        root (string): Root directory of dataset where ``processed/training.pt``
+            and  ``processed/test.pt`` exist.
+        train (bool, optional): If True, creates dataset from ``training.pt``,
+            otherwise from ``test.pt``.
+        download (bool, optional): If true, downloads the dataset from the internet and
+            puts it in root directory. If dataset is already downloaded, it is not
+            downloaded again.
+        transform (callable, optional): A function/transform that  takes in an PIL image
+            and returns a transformed version. E.g, ``transforms.RandomCrop``
+        target_transform (callable, optional): A function/transform that takes in the
+            target and transforms it.
     """
     urls = [
         'http://fashion-mnist.s3-website.eu-central-1.amazonaws.com/train-images-idx3-ubyte.gz',