Added more information to readme.

README.md

@@ -3,6 +3,39 @@
 This repository contains simple example of daemon for Linux OS.
 This repository also contains examples of starting scripts.
 
+When you want to create super simple daemon, then it is very easy.
+You can write something like this in C and call it `daemon.c`:
+
+```c
+/* Compile this with gcc -o daemon daemon.c */
+
+#include <unistd.h>
+
+int main(void)
+{
+    while(1) {
+        /* TODO: do something usefull here ;-) */
+        sleep(1);
+    }
+}
+```
+
+and write some super simple systemd service file called `simple-daemon.service`:
+
+    [Unit]
+    Description=Super simple daemon
+
+    [Service]
+    Type=simple
+    ExecStart=/usr/bin/daemon
+
+    [Install]
+    WantedBy=multiuser.agent
+
+and then you can run it as UNIX daemon, but such daemon do not have some
+nice features like reloadin configure files, loging, etc. This repository
+and sources can help you to understand how UNIX daemons works. 
+
 ## Requirements
 
 To build example of the daemon you have to have following tools
@@ -41,4 +74,6 @@ have a look at command line parameters and arguments
       -p --pid_file  filename   PID file used by daemonized app
 
 When you will run `./bin/daemon` with parameter `--daemon` or `-d`, then
-it will become real UNIX daemon.
+it will become real UNIX daemon. But this is not the way, how UNIX daemons
+are started nowdays. Some init scripts or service files are used for
+this purpose.