docs: more info in readme

README.md

@@ -2,15 +2,64 @@
 
 A simple SMTP server that forwards incoming emails to a Shoutrrr service.
 
+## Installing
+
+First generate a new configuration file following this example:
+
+```toml
+# config.toml
+# Port the SMTP server will listen on
+Port = 11025
+
+# Credentials for the SMTP server (default to username/password if not set/empty)
+Username = "user"
+Password = "nometokens"
+
+# Shoutrrr service to forward emails to
+[[Recipients]]
+# Email addresses to forward emails from
+Addresses = ["some@email.com"]
+# Shoutrrr service to forward emails to
+Target = "ntfy://ntfy.sh/my-ntfy-topic?tags=thing"
+
+# Note: Repeat [[Recipients]] as needed
+```
+
+### From releases
+
+- Grab the latest release from the [releases page](https://git.nakama.town/fmartingr/smtp2shoutrrr/releases)
+- Put the configuration file in the same directory as the binary
+- Run the binary for your appropriate platform
+
+### From source (development)
+
+- Clone [this repository](https://git.nakama.town/fmartingr/smtp2shoutrrr)
+- Put the configuration file in the repository folder
+- Run `make quick-run`
+
+### Using docker
+
+- Create a `config.toml` file as described above
+- Run the docker image mounting the `Config.toml` file as `/config.toml` and exposing the configured port:
+
+```bash
+docker run -v /path/to/config.toml:/config.toml \
+    -p 11025:11025 \
+    git.nakama.town/fmartingr/smtp2shoutrrr:latest
+```
+
 ## Development
 
 Run the server with:
 
 ```
-go run main.go
+make quick-run
 ```
 
 Send a test email with:
 
+> This will read the `config.toml` in the current directory to set the appropriate SMTP client configuration.
+
+```
+go run ./cmd/sendmail/.
 ```
-go run ./cmd/sendmail/main.go