Code setup (#2)

Repository and code setup, including the following features:
- NextJS project from create-next-app for frontend
- Node & Express.js server with MongoDB connection for backend
- Environment variable definitions for both frontend and backend, with example .env files
- Firebase SDKs and configuration for both frontend and backend, and a Firebase project
- A development Gmail account and app password, allowing us to send emails from our backend using nodemailer package
- Unit tests using Jest for both frontend and backend
- Linter & formatter using ESLint & Prettier, run on every commit using Husky
- GitHub Actions workflows to run lint and formatting checks, compilation, and unit tests on every PR to main branch
- README.md updated with instructions to run the project

.github/workflows/lint-check.yml

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+name: Lint, style, and compilation checks
+
+on:
+  pull_request:
+    branches: 
+      - main
+
+jobs:
+  backend:
+    name: Backend check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+      - working-directory: backend
+        run: |
+          npm ci
+          npm run lint-check
+  frontend:
+    name: Frontend check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+      - working-directory: frontend
+        run: |
+          npm ci
+          npm run lint-check
+          npm run build

.github/workflows/unit-tests.yml

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+name: Run frontend & backend unit tests
+on:
+  pull_request:
+    branches: 
+      - main
+jobs:
+  backend:
+    name: Backend tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+      - name: Run tests
+        working-directory: backend
+        env:
+          CI: true
+        run: |
+          npm ci
+          npm run test
+  frontend:
+    name: Frontend tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+      - name: Run tests
+        working-directory: frontend
+        env:
+          CI: true
+        run: |
+          npm ci
+          npm run test

.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+.pnpm-debug.log*
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+*.lcov
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# Snowpack dependency directory (https://snowpack.dev/)
+web_modules/
+
+# TypeScript cache
+*.tsbuildinfo
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional stylelint cache
+.stylelintcache
+
+# Microbundle cache
+.rpt2_cache/
+.rts2_cache_cjs/
+.rts2_cache_es/
+.rts2_cache_umd/
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variable files
+.env
+.env.development.local
+.env.test.local
+.env.production.local
+.env.local
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+.parcel-cache
+
+# Next.js build output
+.next
+out
+
+# Nuxt.js build / generate output
+.nuxt
+dist
+
+# Gatsby files
+.cache/
+# Comment in the public line in if your project uses Gatsby and not Next.js
+# https://nextjs.org/blog/next-9-1#public-directory-support
+# public
+
+# vuepress build output
+.vuepress/dist
+
+# vuepress v2.x temp and cache directory
+.temp
+.cache
+
+# Docusaurus cache and generated files
+.docusaurus
+
+# Serverless directories
+.serverless/
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# TernJS port file
+.tern-port
+
+# Stores VSCode versions used for testing VSCode extensions
+.vscode-test
+
+# yarn v2
+.yarn/cache
+.yarn/unplugged
+.yarn/build-state.yml
+.yarn/install-state.gz
+.pnp.*
+
+# Miscellaneous
+.DS_Store

.husky/lint-config.sh

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+# This config file is sourced by the pre-commit script.
+
+# Change 1 to 0 to disable linting.
+enabled=1
+
+# Directories containing Node.js projects to be linted, separated by spaces.
+node_dirs='backend frontend'
+
+# Command used to run a lint check.
+check_command='npm run lint-check'
+
+# Command used to autofix lint errors.
+fix_command='npm run lint-fix'
+
+# Escape sequences for formatted output.
+format_error="$(tput setaf 3 2> /dev/null)"
+format_warn="$(tput setaf 1 2> /dev/null)"
+format_clear="$(tput sgr0 2> /dev/null)"
+
+# The preceding commands may fail in environments where tput is not available.
+# Return 0 explicitly to indicate that the config was sourced successfully.
+return 0