add instructions for modifying

deploy-container/README.md

@@ -9,6 +9,31 @@ An container image built for deploying code-server.
 
 Docker Hub: `bencdr/code-server-deploy-container`
 
+## Modifying your code-server environment:
+
+We've included some examples on how to add additoonal dependencies in the root-level [Dockerfile](../Dockerfile):
+
+```Dockerfile
+...
+
+# You can add custom software and dependencies for your environment below
+# -----------
+
+# Install a VS Code extension:
+# Note: we use a different marketplace than VS Code. See https://github.com/cdr/code-server/blob/main/docs/FAQ.md#differences-compared-to-vs-code
+RUN code-server --install-extension esbenp.prettier-vscode
+
+# Install apt packages:
+RUN sudo apt-get install -y ubuntu-make
+
+# Copy files: 
+COPY deploy-container/myTool /home/coder/myTool
+
+# -----------
+
+...
+```
+
 ---
 
 ## Environment variables: