update install instructions

README.md

@@ -1,5 +1,8 @@
 # potomark is a simple bookmarking discord bot.
-there's no configuration besides a `.env` file that stores the bot's token.
+there's no configuration besides a `.env` file with two keys:
+
+- the bot's token `DISCORD_TOKEN`,
+- channel id for a sentence game `SENTENCE_CHANNEL`. if you don't want to enable the sentence game, set the key to `-1`.
 
 ## why?
 because we needed a tiny, self hostable bot to remember things of importance for our equally tiny discord server.
@@ -9,8 +12,12 @@ DMs a user a link to any message they reacte with 🔖 to (tip: you can change t
 
 ## how?
 requires [ruby](https://www.ruby-lang.org/) >= 3.0 and [bundler](https://bundler.io) >= 2.3.19. the only two dependencies are `dotenv` and `discordrb`, as specified in the `Gemfile`.
+
+quick setup:
 ```bash
+$ git clone https://git.poto.cafe/yagich/potomark-bot-rb.git && cd potomark-bot-rb
 $ echo 'DISCORD_TOKEN=YOUR.DISCORD.TOKEN.HERE' > .env
+$ echo 'SENTENCE_CHANNEL=SENTENCE_GAME_CHANNEL_ID' >> .env
 $ bundle install
 $ ruby bot.rb
 ```