feat(config): split on __, allowing for setting individual values in a table

docs/configuration.md

@@ -6,6 +6,8 @@
 
 > **Note:** If you update the configuration file, you must restart Conduit for the changes to take effect
 
+> **Note:** You can also configure Conduit by using `CONDUIT_{field_name}` environment variables. To set values inside a table, use `CONDUIT_{table_name}__{field_name}`. Example: `CONDUIT_SERVER_NAME="example.org"`
+
 Conduit's configuration file is divided into the following sections:
 
 - [Global](#global)

src/main.rs

@@ -57,7 +57,7 @@ async fn main() {
                 ))
                 .nested(),
             )
-            .merge(Env::prefixed("CONDUIT_").global());
+            .merge(Env::prefixed("CONDUIT_").global().split("__"));
 
     let config = match raw_config.extract::<Config>() {
         Ok(s) => s,