Docker build name must be to lowercase over OS X

[ak1t4]

MacBook-Pro-de-akita:BlackWidow ak1t4$ docker build -t BlackWidow .
invalid argument "BlackWidow" for "-t, --tag" flag: invalid reference format: repository name must be lowercase

must be:

MacBook-Pro-de-akita:BlackWidow ak1t4$ docker build -t blackwidow .
Sending build context to Docker daemon  606.7kB

[ak1t4]

For run the docker is the same:

MacBook-Pro-de-akita:BlackWidow ak1t4$ docker run -it BlackWidow docker: invalid reference format: repository name must be lowercase. See 'docker run --help'.

Working ok:

MacBook-Pro-de-akita:BlackWidow` ak1t4$ docker run -it blackwidow

                _.._
              .'    '.
             /   __   \ 
          ,  |   ><   |  ,
         . \  \      /  / .
          \_'--`(  )'--'_/
            .--'/()'--.
     1N3   /  /` '' `\  \ 
             |        |
              \      /


 + -- --=[https://crowdshield.com
 + -- --=[blackwidow v1.0

[1N3]

Thanks, I'll update the README with the proper command usage.