feat: Add Makefile for development setup and installation instructions

Author: francescolofranco

Makefile

@@ -0,0 +1,20 @@
+POETRY_VERSION ?= 2.0.1
+
+.PHONY: install-pip
+install-pip:
+	python -m pip install --upgrade pip
+
+.PHONY: install-poetry
+install-poetry:
+	curl -sSL https://install.python-poetry.org | python3 - --version ${POETRY_VERSION}
+
+.PHONY: install-packages
+install-packages:
+	poetry install --no-root $(opts)
+
+.PHONY: install
+install: install-pip install-poetry install-packages
+
+.PHONY: lint
+lint:
+	poetry run pre-commit run -a

README.md

@@ -1,2 +1,48 @@
 # flagsmith-common
 A repository for including code that is required in multiple flagsmith repositories
+
+### Development Setup
+
+This project uses [Poetry](https://python-poetry.org/) for dependency management and includes a Makefile to simplify common development tasks.
+
+#### Prerequisites
+
+- Python >= 3.8
+- Make
+
+#### Installation
+
+You can set up your development environment using the provided Makefile:
+
+```bash
+# Install everything (pip, poetry, and project dependencies)
+make install
+
+# Individual installation steps are also available
+make install-pip       # Upgrade pip
+make install-poetry    # Install Poetry
+make install-packages  # Install project dependencies
+```
+
+By default, Poetry version 2.0.1 will be installed. You can specify a different version:
+
+```bash
+make install-poetry POETRY_VERSION=2.1.0
+```
+
+#### Development
+
+Run linting checks using pre-commit:
+
+```bash
+make lint
+```
+
+Additional options can be passed to the `install-packages` target:
+
+```bash
+# Install with development dependencies
+make install-packages opts="--with dev"
+
+# Install with specific extras
+make install-packages opts="--extras 'feature1 feature2'"