* DockerHub-README.md: reword ambiguous command
Being unfamiliar with the docker options, I thought the square brackets could be part of the command.
Instead, they refer to the sentence *after* the command, that is, they meant "optionally".
To remove the ambiguity, I put into onto different lines with an explanation.
* DockerHub-README.md: reword again, -v by default
- only leave the command with -v as an example
- grammar
- httpS link
Vadim