Slack application: Create landing page
The landing page is needed to make it possible to implement "Slack directory -> GitLab flow". The one who installs Slack application will be redirected to this page and will be able to enable the GitLab Slack application for any particular project.
The page should describe how to enable Slack application for a project for unauthorized user and show a project dropdown for authenticated people. This is a part of Slack App Directory Checklist
Requirements:
Review your installation landing page.
My landing page contains a detailed summary of what my app does and how it integrates with Slack.
My landing page contains clear instructions on how to install and use my app (e.g. which parts of my app trigger messages in Slack, and which comments a bot responds to).
My app's landing page displays the Add To Slack button for users to install my app, or has detailed instructions about how to access the Slack button if behind a login page.
My app has posted a clear privacy policy in English that details how my app will be using any third-party data.
/cc @victorwu