Load custom data from .csv

Process to follow:
1. Install spotlight using virtualenv PR: maciejkula#123
2. run python setpy.py install

spotlight/datasets/custom_dataset.py

@@ -0,0 +1,37 @@
+"""
+Utilities for fetching the custom dataset from local filepath.
+"""
+
+import os
+
+#import h5py
+import numpy as np
+import torch
+
+from spotlight.datasets import _transport
+from spotlight.interactions import Interactions
+
+def _get_custom_dataset(dataset):
+    extension = '.csv'
+    URL_PREFIX = '/home/***/****/*****/********2017_05_01/'
+
+    data = np.genfromtxt(URL_PREFIX + dataset + extension, delimiter=',', names=True, dtype=(int, int, int, int))
+
+    user_ids = data['user_id']
+    product_ids = data['product_id']
+    ratings = data['product_id_total_orders']
+
+    return (user_ids, product_ids, ratings)
+
+def get_dataset(datafile):
+    """
+    Returns
+    -------
+
+    Interactions: :class:`spotlight.interactions.Interactions`
+        instance of the interactions class
+    """
+
+    url = datafile
+
+    return Interactions(*_get_custom_dataset(url))