Shortens urls in chat.
In order to run the application, one must first add a Discord bot token to bot.token in the token.properties file.
Note that a bot token should never be committed in git!
When running directly using java -jar you can also pass your token as a first run argument instead. This is also the used approach in the Dockerfile.
When running the application from the Dockerfile make sure to add the following environment variables, so they can be picked up in the underlying java -jar entrypoint command:
BOT_TOKEN: Discord bot token;API_KEY: shortener's API key;WORKSPACE_ID: shortener's workspace id.
If you didn't create a bot account yet, navigate to https://discordapp.com/developers/applications while logged in. From there, create a new application. In the left panel you will have a 'Bot' section. When a new bot is added, the necessary token will become available. Since the token provides access to the bot, make sure to never share it.
While still in the developer portal in your application context, navigate to 'OAuth2' in the left panel. Under 'scopes', tick the 'bot' checkbox to retrieve an invitation url for your bot. If the bot needs any permissions, make sure to tick them in the 'bot permissions' section. When ready, navigate to the generated url and add your bot to the target server.
When the bot is running, you will now see it appear in the member list of your server in the Discord app.