Update README.md (#76)

Co-authored-by: Hendrik van der Stok <[email protected]>

README.md

@@ -33,8 +33,7 @@ To install all dependencies, you need python installed (>= 3.7).
 If you don't have python or don't want to install it, just clone the required libraries manually. 
 You can extract the relevant information from the `dependencies.cfg` script.
 
-Using the script, it's just:
-
+To install, open a command line interface in the folder of BESMod and run:
 ```python
 python install_dependencies.py full
 ```

install_dependencies.py

@@ -2,6 +2,7 @@
 import sys
 import pathlib
 import json
+from subprocess import check_output, STDOUT, CalledProcessError
 
 
 class LibraryInstaller:
@@ -56,6 +57,13 @@ def install_dependencies(
     for optional_dependency in optional_dependencies:
         if optional_dependency not in optional_dependencies_config:
             raise KeyError(f"Given dependency '{optional_dependency}' is not supported.")
+        if optional_dependency == "Buildings":
+            try:
+                check_output(['git', 'lfs', 'version'], stderr=STDOUT)
+            except CalledProcessError:
+                raise ModuleNotFoundError(
+                    "The optional requirement Buildings requires git large-file-storage (git lfs).\n"
+                    "Install it when you want to use this library.")
         install_libraries[optional_dependency] = optional_dependencies_config[optional_dependency]
 
     open_models = []