Add more content to README.md

README.md

@@ -1,3 +1,23 @@
 # libsccolor
 
-Color representations and color space conversions
+Color representations and color space conversions.
+
+## Build
+
+No external dependencies, so
+
+`make`
+
+will do.
+
+## Install
+
+`sudo make install`
+
+or, on OpenBSD:
+
+`doas gmake install`
+
+## Documentation
+
+Not yet available.