Link api key dev portal on readme

README.md

@@ -47,7 +47,7 @@ With those steps complete, Robin AI will automatically run every time a pull req
 | Name | Required | Default Value | Description |
 |---------------------|----------|---------------------------|-------------------------------------------------------------------------------------------------------------------|
 | `GITHUB_TOKEN` | Yes | Automatically supplied | A Github access token with the `repo` and `pull_request` scopes. |
-| `OPEN_AI_API_KEY` | Yes | N/A | An API key from Open AI's developer portal. |
+| `OPEN_AI_API_KEY` | Yes | N/A | An API key from Open AI's [developer portal](https://platform.openai.com/account/api-keys). |
 | `gpt_model_name` | No | `gpt-3.5-turbo` | The name of the GPT model to use for text generation. |
 | `github_api_url` | No | `https://api.github.com` | The URL for the Github API endpoint. (Only relevant to enterprise customers.) |
 | `root_language` | No | to infer | The primary coding language of the project. |