Update README.md

Author: North-West-Wind

README.md

@@ -4,6 +4,7 @@ Written in Java. Designed for all platform and portable use.
 1. Download the "curseforge.zip" at the [release page](https://github.com/North-West-Wind/CurseForge-CLI/releases/latest).
 2. Extract it to your desire location.
 3. Open a terminal in the extracted folder.
+4. If you're using Linux, make the "curseforge" file executable.
 
 ### Commands
 - `help` Display commands of the program.
@@ -30,4 +31,4 @@ When you run the CLI, you should see a new file called `cf.json`. It is essentia
 You will find modpack/mod name with some numbers after it. That is totally intentional. Do not attempt to remove it. It is used for recognition.
 
 ## License
-GNU GPLv3
+GNU GPLv3