Update README.md

Closes #10

Author: professor

README.md

@@ -10,6 +10,9 @@ View code ownership for every file right in the status bar. You'll get the name
 
 Quick access to the owning team's config file. Clicking on the status bar item will open a popup that includes a button that opens the team's config file. See [Code Teams](https://github.com/rubyatscale/code_teams) for more information on team config files.
 
+## Installation
+[Install from Marketplace](https://marketplace.visualstudio.com/items?itemName=Gusto.code-ownership-vscode)
+
 ## Requirements
 
 This extension runs the [CodeOwnership](https://github.com/rubyatscale/code_ownership) CLI. You'll need to install and configure [CodeOwnership](https://github.com/rubyatscale/code_ownership) in your repository before using this extension. (Before it's set up, you'll see `Owner: error!` in the status bar.)