* Update docker.md
Few Edits:
- Use the `latest` version of polkadot.
- Add a missing `--` when reporting the version.
* Update docker.md use `westend` chain
> Alex doesn't exist anymore, the current test net is `westend`.
According to https://github.com/paritytech/polkadot/issues/803
* update version to 0.3.14 and add --chain alex
- update to latest docker polkadot version - 0.3.14
- add the `--chain alex` argument which is necessary for the Alexander testnet
* add custom node name
add custom node name
* docs: Update Readme for PoC-3
* docs: Fix formatting and update Docker section
* docs: Fix formatting. Start trying to make consistent with Substrate repo
* docs: Move Two-Node example into Hack on Substrate