Update README.md

# Cargo

<div align="center">

<h1> Cargo </h1>

[![build status)](https://img.shields.io/gitlab/pipeline-status/hpc/cargo?gitlab_url=https%3A%2F%2Fstorage.bsc.es%2Fgitlab%2F&logo=gitlab)](https://storage.bsc.es/gitlab/hpc/cargo/-/pipelines)

[![latest release](https://storage.bsc.es/gitlab/hpc/cargo/-/badges/release.svg)](https://storage.bsc.es/gitlab/hpc/cargo/-/releases)

[![GitLab (self-managed)](https://img.shields.io/gitlab/license/hpc/cargo?gitlab_url=https%3A%2F%2Fstorage.bsc.es%2Fgitlab)](https://storage.bsc.es/gitlab/hpc/cargo/-/blob/main/COPYING)

[![Language](https://img.shields.io/static/v1?label=language&message=C99%20%2F%20C%2B%2B20&color=red)](https://en.wikipedia.org/wiki/C%2B%2B20)

<p><b>A parallel data staging service for HPC clusters</b></p>

</div>

Cargo is a HPC data staging service that runs alongside applications helping 

them to transfer data in parallel between local and shared storage tiers.

## Testing

Tests can be run automatically with CTest:

```shell

cd build

ctest -VV --output-on-failure --stop-on-failure -j 8

```

When this happens, a Cargo server with 3 workers is automatically started

(via `mpirun`/`mpiexec`) and stopped (via RPC) so that tests can progress.

Alternatively, during development one may desire to run the Cargo server

manually and then the tests. In this case, the following commands can be used:

```shell

cd build/tests/

mpirun -np 4 ${INSTALL_DIR}/bin/cargo -C

./tests -S ofi+tcp://127.0.0.1:62000

# start the Cargo server with 3 workers. The server will be listening on

# port 62000 and will communicate with workers via MPI messages. The server can

# be stopped with Ctrl+C, `kill -TERM <pid>` or `cargo_shutdown <address>`.)

mpirun -np 4 ${INSTALL_DIR}/bin/cargo -l ofi+tcp://127.0.0.1:62000

# run the tests

cd build

RUNNER_SKIP_START=1 ctest -VV --output-on-failure --stop-on-failure -j 8

```