diff --git a/.gitignore b/.gitignore
index 3ac6e56..b6889c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 .idea/
+Pipfile.lock
 
 # Byte-compiled / optimized / DLL files
 __pycache__/
diff --git a/README.md b/README.md
index 3380cc9..59b86bb 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,8 @@ A command line application and Python library for generating binary numbers for
 ```make_binary_problems <number_of_bits: integer> <number_of_problems: integer>```
 
 ## TODO
+- add installation of ghostscript as a prereq
+  - brew install ghostscript or...?
 - use click to make it a proper CLI, now that there will be multiple options
 - make it produce printable sheets, probably as PDFs
   - add nice spacing for easy reading