docs: Clarify Source & Sinks in the documentation. (#59)

The README wasn't using the same terminology as the config. When I arrived at the config section, I was confused as to what a sink was.

Author: kusold

README.md

@@ -17,11 +17,13 @@ You can read more about inhooks in the [launch blog post](https://didil.medium.c
 ![Inhooks Architecture](inhooks-architecture.png?raw=true "Inhooks Architecture")
 
 ### High level overview
-Inhooks listens to HTTP webhooks and saves the messages to Redis. A processing module retrieves the messages and sends them reliably to the defined targets.
+Inhooks consists of two major concepts, Sources and Sinks. A Source is an endpoint for receiving webhooks, and a [Sink](https://en.wikipedia.org/wiki/Sink_(computing)) is a target that receives the webhooks.
+
+Inhooks listens to HTTP webhooks and saves the messages to Redis. A processing module retrieves the messages and sends them reliably to the defined sinks.
 
 ## Features
 - Receive HTTP Webhooks and save them to a Redis database
-- Fanout messages to multiple HTTP targets
+- Fanout messages to multiple HTTP targets (sinks)
 - Fast, concurrent processing
 - Supports delayed processing
 - Supports retries on failure with configurable number of attempts, interval and constant or exponential backoff
@@ -219,4 +221,4 @@ Feel free to open new issues or PRs ! You can also reach out to the maintainer a
 Copyright (c) 2023 Adil H.
 
 Inhooks is an Open Source project licensed under the terms of the LGPLv3 license.
-Please see [LICENSE](LICENSE) for the full license text.
+Please see [LICENSE](LICENSE) for the full license text.