Update README

README.md

@@ -1,18 +1,44 @@
 # telegram-group2mastodon
 
 telegram-group2mastodon is a Telegram bot to post messages from a Telegram
-group to Mastodon. You should only use on public groups and set the bot to be
-able to read all the messages.
+group to Mastodon. It's written in Go and it is relased under the AGPL3+.
+Since the bot must be able to read all the messages you should use it only on
+public groups.
 
-**This is still a Work In Progress, please don't use at the moment, since also
-documentation is missing.**
+## Installation
 
-## TODO
+1. Build the bot (for example if version is v0.1.0 and you are on a unix system):
+   ```
+   cd /tmp; GOPATH=/tmp/go go install noa.mornie.org/eriol/telegram-group2mastodon@v0.1.0
+   ```
+   You will find the binary at `/tmp/go/bin/telegram-group2mastodon`. You don't
+   need to set `GOPATH` if you already have it set and you are fine having the
+   bot installed there.
 
-- [x] Publish text messages from Telegram to Mastodon.
-- [x] Handle text > 500 characters (or mastodon instance limit).
-- [x] Handle messages with 1 photo and caption.
-- [x] Handle messages with multiple photos.
-- [x] Add configuration variable to set mastodon message visibility.
-- [x] Set the Telegram channel allowed to use the bot: we don't want spam from
-      someone that just add the bot somewhere.
+2. Create your bot using Telegram @BotFather.
+
+3. The bot uses environment variables as configuration, you have to export
+   the following (except variables with a default) before starting it:
+   | Variable                       | Meaning                      | Default  |
+   |--------------------------------|------------------------------|----------|
+   | `MASTODON_ACCESS_TOKEN`        | Mastodon access token        | *N/A*    |
+   | `MASTODON_SERVER_ADDRESS`      | Mastodon server address      | *N/A*    |
+   | `MASTODON_TOOT_MAX_CHARACTERS` | Toot max lenght              | 500      |
+   | `MASTODON_TOOT_VISIBILITY`     | Default toot visibility      | unlisted |
+   | `TELEGRAM_BOT_TOKEN`           | Telegram bot token           | *N/A*    |
+   | `TELEGRAM_CHAT_ID`             | Telegram alolowed chat id    | *N/A*    |
+   | `TELEGRAM_DEBUG`               | Debug messages from Telegram | False    |
+
+   `MASTODON_TOOT_VISIBILITY` allowed values are: `direct`, `private`, `public`
+   and `unlisted`.
+   To get `MASTODON_ACCESS_TOKEN` see next point.
+4. To get `MASTODON_ACCESS_TOKEN` use the subcommand `authenticate`:
+   ```
+   telegram-group2mastodon authenticate
+   ```
+   and follow the istructions.
+
+5. Launch the bot:
+   ```
+   telegram-group2mastodon run
+   ```