Build docker image from Dockerfile

[darionyaphet]

Docker can build images automatically by reading the instructions from a Dockerfile.

A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image.

Using docker build users can create an automated build that executes several command-line instructions in succession.

[sherman-the-tank]

We need to figure out where to store these docker files and some other scripts

[darionyaphet]

refer to pingcap/tidb, we can put it under the root directory.