Fix Docker build failure and configuration issues

[ansh0014]

• Update Dockerfile from Go 1.14 to Go 1.21-alpine
• Implement multi-stage build for smaller image size
• Add MySQL root password in docker-compose.yaml
• Fix article-server command path (article-server -> ./article-server)
• Add proper volume mount for config file (local.yaml -> config.yaml)
• Add depends_on to ensure MySQL starts before article-server
• Include build context and dockerfile specification

These changes resolve Docker build failures and runtime configuration errors."

[ansh0014]

Problem

• Docker build failed due to outdated Go version (1.14)
• Missing MySQL credentials in docker-compose
• Incorrect article-server command path
• Missing volume mounts for config and migrations

Solution

• Updated Dockerfile to use golang:1.21-alpine
• Added MySQL environment variables to docker-compose
• Fixed article-server command path
• Added volume mounts for config and migration files
• Added depends_on to ensure correct startup order

Testing

• Docker build completed successfully
• All containers running as expected
• Article server accessible on port 8080
• MySQL connection verified
  #Issue No.
  [Docker Build Failure due to GoLang Version 1.14 #2]