readme update.

README.md

@@ -42,11 +42,12 @@ argonix shell --help
 ```
 
 ``` {.txt}
-Usage: argonix shell TARGET [--argopkgs ARGOPKGS] [-v|--verbose] [--aml PATH]
+Usage: argonix shell TARGET [--argopkgs ARGOPKGS] [-v|--verbose]
+                     [-s|--sandboxing] [-g|--grafting] [--aml PATH]
                      [--libnrm PATH] [--nrm PATH] [--containers PATH]
                      [--argotk PATH] [--amg PATH] [--lammps PATH]
                      [--qmcpack PATH] [--stream PATH] [--openmc PATH]
-                     [--run COMMAND]
+                     [--experiments PATH] [--run COMMAND]
   Enter an argo-compatible nix-shell
 
 Available options:
@@ -54,6 +55,9 @@ Available options:
   --argopkgs ARGOPKGS      Nix expression that produces the argopkgs source
                            path. (default: "<argopkgs>")
   -v,--verbose             Enable verbose mode
+  -s,--sandboxing          Enable nix sandboxing.
+  -g,--grafting            Enable libnrm grafting to avoid rebuilding
+                           applications.
   --aml PATH               aml source folder override.
   --libnrm PATH            libnrm source folder override.
   --nrm PATH               nrm source folder override.
@@ -64,6 +68,7 @@ Available options:
   --qmcpack PATH           qmcpack source folder override.
   --stream PATH            stream source folder override.
   --openmc PATH            openmc source folder override.
+  --experiments PATH       experiments source folder override.
   --run COMMAND            Command to run the environment instead of an
                            interactive shell
   -h,--help                Show this help text