Add welcome message

.devcontainer/devcontainer.json

@@ -2,15 +2,12 @@
 {
 	"name": "pallets/flask",
 
-	// Features to add to the dev container. More info: https://containers.dev/features.
-	// "features": {},
+	// Displays a custom welcome message
+	"onCreateCommand": "sudo cp .devcontainer/welcome-message.txt /usr/local/etc/vscode-dev-containers/first-run-notice.txt",
 
 	// Runs the initial setup commands after the container is created.
-	"postCreateCommand": "sudo chmod +x .devcontainer/post-create-command.sh && .devcontainer/post-create-command.sh"
+	"postCreateCommand": "sudo chmod +x .devcontainer/post-create-command.sh && .devcontainer/post-create-command.sh",
 
     // Activates the virtual environment after the container is started.
-	// "postStartCommand": ". .venv/bin/activate"
-
-	// Configure tool-specific properties.
-	// "customizations": {},
+	"postStartCommand": ". .venv/bin/activate"
 }

.devcontainer/post-create-command.sh

@@ -4,12 +4,10 @@ set -e
 # Add user's fork as a remote
 GIT_USER=$(git config user.name)
 git remote add fork https://github.com/${GIT_USER}/flask
-echo "Added remote"
 
 # Create and activate a virtualenv
 python3 -m venv .venv
 . .venv/bin/activate
-echo "Created virtualenv"
 
 # Upgrade pip and setuptools
 python -m pip install --upgrade pip setuptools

.devcontainer/welcome-message.txt

@@ -0,0 +1,7 @@
+👋  Welcome to Flask in Codespaces!
+
+🛠️  Your environment is setup with all the required dependencies and your fork has been added as a remote.
+
+📝  Wait for the "postCreateCommand" to finish setting things up, then run `. .venv/bin/activate` to activate your virtualenv.
+
+🚀  To start coding, checkout a branch from the latest release for bugs or docs fixes, or from main for new feature work.