feat(infra): add Docker setup for backend service

This commit introduces the initial infrastructure for the HR platform, as defined by the responsibilities of Agent 1. It includes:

- A `Dockerfile` for building the Node.js application container.
- A `docker-compose.yml` file to orchestrate the `api` and `db` services.
- An `.env.example` file to define the required environment variables.
- A `.gitignore` file to exclude unnecessary files from version control.
- A log file in `docs/agents/agent-01-infraestructura.md` to document the changes.

.gitignore

@@ -0,0 +1,74 @@
+# Dependencies
+/node_modules
+
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# 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
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-temporary-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+jspm_packages/
+
+# TypeScript v1 declaration files
+typings/
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# 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 variables file
+.env
+.env.test
+.env.production
+
+# Mac files
+.DS_Store
+
+# VSCode files
+.vscode/