Example bugfix

[LeoniePhiline]

Hi!

Thanks for this little helper :)

There is an issue with example 2:

docker container run --rm -it -e var=value -v $(pwd):/wd bhgedigital/envsubst sh -c "envsubst < /wd/file.txt > file-subst.txt" && cat file-subst.txt

The envsubst stdout goes to file-subst.txt in the current container working directory (/ in default alpine).

Fixed in-container command:

envsubst < /wd/file.txt > /wd/file-subst.txt