Update README.md

Forgot to add the license on initial publication.

README.md

@@ -29,4 +29,10 @@ co2_eq_emissions:
 - Precision: 0.938
 - Recall: 0.978
 - AUC: 0.980
-- F1: 0.958
+- F1: 0.958
+
+# License Notice
+
+This work is licensed under a [Creative Commons Attribution-NoDerivatives 4.0 International License](https://creativecommons.org/licenses/by-nd/4.0/).
+
+You may distribute and make this model available to others as part of your own web page, app, or service so long as you provide attribution. However, use of this model within text-to-image systems to evade AI image detection would be considered a "derivative work" and as such prohibited by the license terms.