add http server

readme.md

@@ -16,3 +16,29 @@ Plans to add the following databases:
 TODO, but!
 
 All dependencies will be covered by docker.
+
+## Architecture
+
+This application contains just of two layers:
+
+- External Layer that accepts http connections
+- Store Layer that stores entities inside some store hidden by implementation for specific database.
+
+During to simple logic, there is no need to add additional business-logic layer since its all about
+saving incoming metrics into database.
+
+### External Layer
+
+Typically simple HTTP Server which allows to interact with application by the following handlers:
+
+| Handler       | Request                   | Parameters                                                                          | Description                         |
+| ------------- | ------------------------- | ----------------------------------------------------------------------------------- | ----------------------------------- |
+| Upsert metric | POST `/api/v1/stats/{id}` | {id} -- ID of the device. String. JSON-encoded body for stats (see below for model) | Upserts stats for the passed device |
+| List metrics  | GET `/api/v1/stats`       | <Not Applicable>                                                                    | Lists all available metrics         |
+
+### Store Layer
+
+Provides two methods to interacts with statistics:
+
+- `List` - list available metrics;
+- `Upsert` - update metric by device id.