docs: create README file with build and run instructions.

Author: gustavosr8

README.md

@@ -0,0 +1,21 @@
+# EPICS IOC for ADEiger-based detectors
+
+This repository contains the EPICS Input/Output Controller (IOC) used at LNLS
+based on [ADEiger](https://github.com/areaDetector/ADEiger) support module.
+
+## Running the IOC
+
+You can use the following command to run it in the background using the `lnls-run.sh` script from
+[epics-in-docker](https://github.com/cnpem/epics-in-docker).
+
+```
+docker compose up -d
+```
+
+## Building the IOC image
+
+You can build the IOC with the following command:
+
+```bash
+TAG=latest docker compose build
+```