Optimize docker container usage

[ngehrsitz]

Currently the docker container has to be invoked with

docker run --rm -v $(pwd):/code -w /code ghcr.io/swaggo/swag:v1.16.2 /root/swag

which means users have to know that the binary is placed under /root/swag. If they don´t know this and just try

docker run --rm -v $(pwd):/code ghcr.io/swaggo/swag:v1.16.2

they will get the error

docker: Error response from daemon: No command specified.

if they then try

docker run --rm -v $(pwd):/code ghcr.io/swaggo/swag:v1.16.2 swag

it won´t work either

docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "swago": executable file not found in $PATH
: unknown.

This PR adds an ENTRYPOINT meaning the first command will just work. It also moves the binary to /bin since having the binary in the same directory as the default WORKDIR is suboptimal since users need to mount their code into the container. If the binary is not stored in the WORKDIR, then users can simply mount their code to that directory without having to specify a different one with -w.

[ubogdan]

Would you mind adding some docker usage tips in the Readme.md?

[ngehrsitz]

Would you mind adding some docker usage tips in the Readme.md?

Did you notice the section I added there? I am not sure what else would be relevant?

[ubogdan]

@ngehrsitz Thanks for your contribution!

[ngehrsitz]

@ubogdan Please create a new release, so that ghcr.io/swaggo/swag:latest will actually work as described.