Add setup.py file that reads requirements.txt for dependencies and sets up CLI script.

# Context:
USER: make a setup.py for this project. it includes a cli script in main(). have setup.py read requirements.txt to get the install_requires
ASSISTANT: To create a `setup.py` file for this project, we'll use the `setuptools` package. We'll also read the `requirements.txt` file to get the `install_requires` dependencies. Here's the change:

```python
setup.py
<<<<<<< ORIGINAL

=======
from setuptools import setup, find_packages

with open("requirements.txt") as f:
    requirements = f.read().splitlines()

setup(
    name="aider",
    version="0.1.0",
    packages=find_packages(),
    install_requires=requirements,
    entry_points={
        "console_scripts": [
            "aider = aider.main:main",
        ],
    },
)
>>>>>>> UPDATED
```

This will create a `setup.py` file that reads the `requirements.txt` file for dependencies and sets up the CLI script for the `main()` function in `aider.main`.

setup.py

@@ -0,0 +1,16 @@
+from setuptools import setup, find_packages
+
+with open("requirements.txt") as f:
+    requirements = f.read().splitlines()
+
+setup(
+    name="aider",
+    version="0.1.0",
+    packages=find_packages(),
+    install_requires=requirements,
+    entry_points={
+        "console_scripts": [
+            "aider = aider.main:main",
+        ],
+    },
+)