Add further explanations to the README file

README.md

@@ -1,3 +1,22 @@
 # docker-keil
-
 A docker image that allows you to run Keil uVision using Wine
+
+## Usage
+This docker image provides a pre-installed Wine installation with a pre-installed copy of "Keil uVision 5".
+Furthermore, a command called `st-compile` is compiled which provides the functionality to build "Keil uVision 5" projects.
+
+The command `st-compile` accepts one parameter:
+
+The path to a project file or the path to a source file which belongs to a "Keil uVision 5" project (such as ASM or C source files).
+
+Usage:
+
+```bash
+st-compile <path-to-project-or-source-file>
+```
+
+This docker image can be built using the following command:
+
+```bash
+docker build -t <tag-name> .
+```