Adding mongodb docs

[Divyapahuja31]

📋 Pull Request Description

What does this PR do?

This PR adds comprehensive MongoDB documentation under the docs/mongodb/ directory, covering essential database concepts, CRUD operations, schema design, aggregation, and Mongoose integration.

Type of Change

• 📝 New documentation
• 📚 New topic/section

Changes Made

• Added setup.md — Introduction and environment setup for MongoDB
• Added crud.md — CRUD operations with examples
• Added schema-design.md — Database schema design best practices
• Added aggregation.md — Aggregation pipeline and examples
• Added mongoose.md — Integration guide for MongoDB with Mongoose

Documentation Location

• Folder: docs/mongodb/
• Files added:
  • setup.md
  • crud.md
  • schema-design.md
  • aggregation.md
  • mongoose.md

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✅ Checklist

General

• My code follows the style guidelines of this project
• I have performed a self-review of my own content
• Markdown formatting is correct
• No warnings or build errors

Documentation

• All examples tested and working
• Code snippets include clear explanations
• File naming follows conventions
• Beginner-friendly yet comprehensive

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🧪 Testing

Test Results

• ✅ Tested locally
• ✅ All examples render correctly
• ✅ No formatting or build issues found

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📚 Additional Context

This addition introduces detailed MongoDB documentation to the devdocx project, aligning with existing backend topics like Node.js, Express, and Prisma.
It helps users learn database design, CRUD patterns, and Mongoose integration through well-structured, example-rich markdown files.

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🎃 Hacktoberfest

• ✅ This PR is part of Hacktoberfest 2025
• ✅ I have read and followed the Contributing Guidelines
• ✅ I have read and agree to the Code of Conduct

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📝 Note to Reviewers

Please review for markdown consistency, code clarity, and completeness across all five MongoDB documentation files.

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📝 Before Merging

• Documentation is clear and accurate
• Code examples work correctly
• No typos or grammatical errors
• Follows project structure and conventions