add image classification example train script

example/image-classification/train.sh

+#!/bin/bash
+set -o nounset
+set -o errexit
+
+script_path=$(cd `dirname $0`; pwd)
+cd $script_path
+
+model_name=ResNet50
+batch_size=32
+data_dir=./dataset
+class_dim=2
+use_gpu=False
+
+while getopts "m:b:c:d:g" options
+do
+	case "$options" in
+        b)
+            batch_size=$OPTARG;;
+        c)
+            class_dim=$OPTARG;;
+        d)
+            data_dir=$OPTARG;;
+		m)
+			model_name=$OPTARG;;
+        g)
+            use_gpu=True;;
+		?)
+			echo "unknown options"
+            exit 1;;
+	esac
+done
+
+python train.py --data_dir=${data_dir} --batch_size=${batch_size} --class_dim=${class_dim} --image_shape=3,224,224 --model_save_dir=output/ --lr_strategy=piecewise_decay --lr=0.1 --model=${model_name} --use_gpu=${use_gpu}