Connect MySQL workbench with MySQL container
It looks like you ran the container without setting the -p 3306:3306 parameter. Also, it seems that you mistyped the IP address in of the Hostname in MySQL Workbench. I recommend starting from scratch by following these instructions:


Run the mysql server. (Change the password admin to anything you want)


docker run -e MYSQL_ROOT_PASSWORD=admin --name mysql -d -p=3306:3306 mysql


get the IP address of the default docker virtual machine by running 


docker-machine ip default


Copy the IP address that you'll get as the result of the previous command. (in your case, it should be 192.168.99.100)
Open MySQL Workbench and create a new connection. Paste the IP address that you copied into the "Hostname" field.


You should be all set now.