Secure hardening: env vars, hashed passwords, input validation, docs

[SamPomeroy]

Overview

This PR implements the required functions and setup for the W0D2 GitHub Classroom assignment.

Changes Made

• Implemented all required functions in assignment.py:
  • reverse_string
  • count_vowels
  • calculate_average
  • find_max_min_diff
  • is_palindrome
• Added .env.example for environment variable guidance
• Updated requirements.txt with necessary dependencies
• Added CONTRIBUTING.md and PULL_REQUEST_TEMPLATE.md for collaboration practices
• Verified functionality with curl requests and local tests

Testing

• Verified assignment.py functions locally with pytest
• Ran Flask server (app.py) and tested /users and /login routes with curl
• Confirmed responses matched expected results

Next Steps

• Await instructor feedback
• Make adjustments if required