[README.md] initial draft of README

Author: chrissimpkins

README.md

@@ -1,2 +1,28 @@
 # set-unicoderange
-Python script to automatically set OpenType OS/2 table Unicode range bit flags
+
+Python script to automatically set the [OpenType OS/2 table Unicode range bit flags](https://docs.microsoft.com/en-us/typography/opentype/spec/os2#ur).
+
+## Dependencies
+
+- Python 3.6+ interpreter
+- [fontTools Python package](https://github.com/fonttools/fonttools)
+
+## Usage
+
+Execute the `src/set-unicoderange.py` script on the command line with one or more font path arguments.
+
+```
+$ python3 set-unicoderange.py [FONT PATH 1] (FONT PATH 2)...(FONT PATH n)
+```
+
+The script detects the code points available in the font and automatically sets the OpenType OS/2.ulUnicodeRange bit flags 1 - 4.
+
+### Example
+
+```
+$ python3 set-unicoderange.py SomeFont-Regular.ttf
+```
+
+## License
+
+Apache License, Version 2.0.  Please see [LICENSE](LICENSE) for details.