Update README.md

README.md

@@ -10,3 +10,16 @@ A basic Electron app that wraps [messages.android.com](https://messages.android.
 
 ["message"](https://thenounproject.com/term/message/849833)
 by Gregor Cresnar from the Noun Project.
+
+## Security Concerns
+
+Being concerned about security and suspicious of third-party apps stealing your data is important. This app does nothing but wrap the Android Messages site in a way that allows it to run independent of a web browser. You can see everything it does in `main.js`. (Disclaimer: I can only guarantee the security of the files in this repository, you'll have to trust Electron yourself.)
+
+If you are still concerned about security (and you should be as a general rule), you can build this yourself by cloning the repository and running the following:
+- `npm install`
+- `npm run build`
+
+Specific build scripts for each OS also exist:
+- `npm run build-darwin`
+- `npm run build-linux`
+- `npm run build-win32`