fix(examples): add explanations about docker group to examples/electr…

…icity-trade and examples/cartrade-2

Signed-off-by: Ryu-Shinzaki <shinzaki.ryu@fujitsu.com>

examples/cartrade/README.md

@@ -103,3 +103,4 @@ Before you begin, you need to check that you have all the prerequisites installe
 1. Stop the docker containers of Ethereum and Fabric
 	- Press the command `docker stop <CONTAINER ID>` to stop the container corresponding to the above containers which were launched by `./script-start-ledgers.sh` on the boot method. If you want to destroy the docker containers, press the command `docker rm <CONTAINER ID>` after the above.
 	- If any other docker containers are not running on your machine, you can destroy the Docker containers only with `docker ps -aq | xargs docker stop` and `docker ps -aq | xargs docker rm`.
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