Repository name must be lowercase

[d6o]

Docker doesn't allow to use Uppercase characters.

Before:

% docker run -it -p 5000:5000 jjangsangy/ExplainToMe:latest
docker: invalid reference format: repository name must be lowercase.
See 'docker run --help'.

After:

% docker run -it -p 5000:5000 jjangsangy/explaintome:latest
Unable to find image 'jjangsangy/explaintome:latest' locally
latest: Pulling from jjangsangy/explaintome
81033e7c1d6a: Pull complete
...