feat: improve README and dev setup

Makefile

@@ -1,7 +1,7 @@
 .PHONY: setup
 setup:
-	pyenv virtualenvs | grep stack-graphs-python-bindings || pyenv virtualenv 3.11.9 stack-graphs-python-bindings
-	pyenv activate stack-graphs-python-bindings
+	python -m venv .venv
+	. .venv/bin/activate
 	pip install maturin
 
 .PHONY: develop

README.md

@@ -15,28 +15,64 @@ pip install stack-graphs-python-bindings # or poetry, ...
 ```
 
 ```python
-from stack_graphs_python import index, query_definition, Position
+import os
+from stack_graphs_python import index, Querier, Position, Language
 
-# ...
+db_path = os.path.abspath("./db.sqlite")
+dir = os.path.abspath("./tests/js_sample")
+
+# Index the directory (creates stack-graphs database)
+index([dir], db_path, language=Language.JavaScript)
+
+# Instantiate a querier
+querier = Querier(db_path)
+
+# Query a reference at a given position (0-indexed line and column): 
+# foo in: const baz = foo
+source_reference = Position(path=dir + "/index.js", line=2, column=12)
+results = querier.definitions(source_reference)
+
+for r in results:
+    print(f"{r.path}, l:{r.line}, c: {r.column}")
 ```
 
-You can refer to the example in [test/test.py](https://github.com/nohehf/stack-graphs-python-bindings/blob/main/tests/test.py) for a concrete usage example.
+Will result in:
+
+```bash
+[...]/stack-graphs-python-bindings/tests/js_sample/index.js, l:0, c: 9
+[...]/stack-graphs-python-bindings/tests/js_sample/module.js, l:0, c: 13
+```
+
+That translates to:
+
+```javascript
+// index.js
+import { foo } from "./module"
+
+// module.js
+export const foo = "bar"
+```
 
 ## Development
 
 ### Ressources
 
 https://pyo3.rs/v0.21.2/getting-started
 
+### Requirements
+
+- Rust
+- Python 3.11+
+
 ### Setup
 
 ```bash
-pipx install maturin # or pip, ...
+# Setup venv and install maturin through pip
+make setup
 ```
 
 ### Testing
 
 ```bash
-maturin develop
-python tests/test.py
+make test
 ```