Add short README, enhance .gitignore

.gitignore

 __pycache__
+venv

README.md

+# 2FA
+
+This is only a quick demo on how you could possible generate a second factor in form of a one-time-password using Python.
+
+If you want to manage all your second factors in one place, this tool is not for you.
+
+## Installation
+
+```bash
+python3 -m venv venv
+source venv/bin/activate
+pip install -r requirements.txt
+```
+
+## Enrollment
+
+Launch a Python shell, e.g., using:
+
+```bash
+source venv/bin/activate
+python3
+```
+
+Within the shell, type:
+
+```python
+from main import enroll_token
+enroll_token("otpauth://totp/...")  # replace this with the URL you've gotten from the 2FA enrollment system
+```
+
+This will only store the token locally in the secret storage, without any validation whatsoever.
+
+## Get token
+
+```bash
+source venv/bin/activate
+./main.py
+```
\ No newline at end of file