feat: add dataset container's example dockerfile

dataset/Dockerfile

@@ -0,0 +1,16 @@
+# we will run `docker run -it --rm -v ./dataset_dir:/dataset YOUR_IMAGE` to run the downloading container.
+# The provider will mount their `dataset_dir` to `/dataset` directory in the container.
+# So, you should save your dataset into `/dataset` so that our `training container` can access your dataset.
+
+FROM ubuntu:22.04
+
+# This is our example script:
+# First, we create the directory named `/dataset` so that it can link to the provider's host.
+# Then, we use apt to download `wget` so that we can use wget to download the dataset from our target URL.
+RUN mkdir /dataset && apt-get update && apt-get install -y wget
+
+# And we get the dataset file from the target URL and save it into /dataset
+# Then, we unzip it so that the `training container` can access them directly.
+WORKDIR /dataset
+CMD pwd && wget https://www.cs.toronto.edu/\~kriz/cifar-10-python.tar.gz && tar zxvf cifar-10-python.tar.gz
+