This is a simple web application written in Go that provides a service to watermark documents. The application is designed for a global publishing company that publishes books and journals. It allows specific users to watermark documents, which have a title, author, and a watermark property that can be in one of three states: Started, InProgress, and Finished.

The publishing company needs a reliable way to protect their intellectual property by adding a watermark to their documents. The watermarking process should be performed by authorized users, and once a document is watermarked, it can never be re-marked.

Here is an example of a document object:

{
  "content": "book",
  "title": "The Dark Code",
  "author": "Bruce Wayne",
  "topic": "Science"
}

The Document Watermarking Service provides the following functionality:

• Allow specific set of users to watermark documents.
• Marking the document in one of three states: Started, InProgress, and Finished.
• Preventing re-marking of a document after it has been watermarked.

In this project, we will have 3 microservices: Authentication Service, Database Service and the Watermark Service. We have a PostgreSQL database server and an API-Gateway.

This application is built using the following technologies:

• Go
• Gin Web Framework
• MongoDB

To use this application, you need to have Go and MongoDB installed on your machine. Follow these steps to get started:

1. Clone the repository to your local machine.
2. Navigate to the project directory and run go mod download to download the required packages.
3. Start the server by running go run main.go.
4. Open your web browser and go to http://localhost:8080 to access the application.

The Document Watermarking Service is a simple but effective solution for protecting the publishing company's intellectual property. It allows authorized users to watermark documents and ensures that once a document is watermarked, it can never be re-marked.