Update README.md

# BoGEMMS-HPC

The Bologna Geant4 Multi-Mission Simulator for HPC

## Building

Clone or unpack the source code in a location of your choice.

> <pathto>/BoGEMMS-HPC

`> <pathto>/BoGEMMS-HPC`

Create a directory in which to configure and run the build and store the build products (not inside the source dir) 

> makedir <pathto>/BoGEMMS-HPC-build

`> makedir <pathto>/BoGEMMS-HPC-build`

To configure, change into the build directory and run CMake

> cd <pathto>/BoGEMMS-HPC-build

> cmake <pathto>/BoGEMMS-HPC

> make

`> cd <pathto>/BoGEMMS-HPC-build`

`> cmake <pathto>/BoGEMMS-HPC`

`> make`

### Building options

-DSQLBUILD=ON -DGEANT4_VERSION=GEANT4_11_1

- Activating SQLite: `-DSQLBUILD=ON` (default=OFF)

- Setting the Geant4 version: `-DGEANT4_VERSION=GEANT4_11_1` (default GEANT4_11_1)

- Activating the ROOT dependance: `-DNOROOTBUILD=OFF` (default=ON)

## Usage

Use examples liberally, and show the expected output if you can. It's helpful to have inline the smallest example of usage that you can demonstrate, while providing links to more sophisticated examples if they are too long to reasonably include in the README.

- Single node (no mpi): `bogemms <conf file> <starting number> <mac file>`

- multinode (with mpi): `mpiexec -n <task number> bogemms <conf file> <starting number> <mac file>`

## Support

Tell people where they can go to for help. It can be any combination of an issue tracker, a chat room, an email address, etc.

Work in progress