update training documentation

README.md

@@ -57,6 +57,22 @@ The classification task is split into two stages:
     - 98.2% on training data, 98.7% accuracy on validation
     - 911,180 rows of 11 features
 
+## Training Features
+I applied cross-validation with `cv=5` to the training dataset to search for the best hyperparameters.
+Here's the dict passed to `GridSearchCV`:
+```python
+params = {
+    'objective': 'binary',
+    'metric': 'binary_logloss',
+    'boosting_type': ['gbdt', 'dart'],
+    'num_leaves': [15, 23, 31, 63],
+    'learning_rate': [0.001, 0.002, 0.01, 0.02],
+    'feature_fraction': [0.5, 0.6, 0.7, 0.9],
+    'early_stopping_rounds': [10, 20],
+    'num_boost_round': [500, 750, 800, 900, 1000, 1250, 2000]
+}
+```
+
 
 ## URL Features
 ```python