update readme

README.md

@@ -56,6 +56,9 @@ $ ./pull-specs.sh
 # If an access token required for https clones from gitlab repositories
 # then this can be specified using:
 $ ./pull-specs.sh --token "ACCESS_TOKEN_HERE"
+
+# You may need to first set the $USER environment variable to match the GitLab account name.
+
 ```
 
 ### Generating the identitylib