README: Explain the new development setup.

README.md

@@ -9,14 +9,39 @@ Python bindings for tantivy.
 
 # Installation
 
-The bindings can be installed using setuptools:
+The bindings can be installed using from pypi using pip:
 
-    python3 setup.py install --user
+    pip install tantivy-py
 
-Note that this requires setuptools-rust to be installed. Another thing to note
-is that the bindings are using [PyO3](https://github.com/PyO3/pyo3), which
+If no binary wheel is present for your operating system the bindings will be
+build from source, this means that Rust needs to be installed before building
+can succeed.
+
+Note that the bindings are using [PyO3](https://github.com/PyO3/pyo3), which
 requires rust nightly and only supports python3.
 
+# Development
+
+Developing tantivy-py can be done in a virtual environment using `pipenv` or
+using local packages using the provided `Makefile`.
+
+For the `pipenv` setup install the virtual environment and build the bindings using:
+
+    pipenv install --dev
+    pipenv run maturin develop
+
+After the bindings are build, the tests can be run using:
+
+    pipenv run python -m pytest
+
+For the `Makefile` based setup run:
+
+    make
+
+Running the tests is done using:
+
+    make test
+
 # Usage
 
 tantivy-py has a similar API to tantivy. To create a index first a schema