Add documentation

Author: enindu

README.md

@@ -1,3 +1,36 @@
 # genimg
 
 genimg is a lightweight tool for generating random images at custom sizes. I often need placeholder images for specific dimensions, and while there are many options available, I wanted a simple, self-hosted solution—so I built this.
+
+## Install
+
+You can install genimg using `go install` command.
+
+```
+go install github.com/enindu/genimg@latest
+```
+
+## Usage
+
+You can run genimg using the following syntax.
+
+```
+genimg <command>:<subcommand> [arguments]
+genimg [flags]
+```
+
+To display the version message:
+
+```
+genimg -v # or "genimg --version"
+```
+
+To display the help message:
+
+```
+genimg -h # or "genimg --help"
+```
+
+## License
+
+This software is licensed under the [GNU General Public License v3.0](https://www.gnu.org/licenses/gpl-3.0.en.html). You can view the full license [here](https://github.com/enindu/genimg/blob/master/COPYING).

help.go

@@ -32,7 +32,9 @@ Available commands:
 Available flags:
 
 	-v, --version # View version message.
-	-h, --help    # View help message.`
+	-h, --help    # View help message.
+	
+Use "genimg <command>:help" to see more information about commands.`
 
 	fmt.Fprintf(os.Stdout, "%s\n", message)
 }

main.go

@@ -14,6 +14,23 @@
 // You should have received a copy of the GNU General Public License along with
 // this program.  If not, see <https://www.gnu.org/licenses/>.
 
+// genimg is a lightweight tool for generating random images at custom sizes.
+//
+// Usage:
+//
+//	genimg <command>:<subcommand> [arguments]
+//	genimg [flags]
+//
+// Available commands:
+//
+//	source
+//
+// Available flags:
+//
+//	-v, --version # View version message
+//	-h, --help    # View help message
+//
+// Use "genimg <command>:help" to see more information about commands.
 package main
 
 import (