Adding Docker build instructions

BUILD.md

@@ -1,7 +1,21 @@
 # Building Resurrection Capsule Server
 
+* [Docker](#docker)
 * [Linux](#linux)
 
+## Docker
+The process of building the ReCap server with a Docker container can be executed from any system, as long as you have Docker installed.
+1. Build the Docker image:
+   ```bash
+   git clone https://github.com/vitor251093/recap_server
+   cd recap_server/
+   docker-compose up
+   ```
+2. Run the Docker container (will build and run the server locally):
+   ```bash
+   docker run -v $(pwd)/darkspore_server:/recap -P --network=host -it recap-server
+   ```
+
 ## Linux
 1. Install dependencies:
    * Ubuntu: `sudo apt install g++-13 cmake libfindbin-libs-perl libstdc++-13-dev build-essential`