Markus and Cjb
I solved it!
It seems that for some reason I am allowed to edit the file in the app package itself.
To others that need to do the same as me - here is my scenario:
I have made a game editor for my game outside of agk. It is made in Livecode. The reason is that its much faster to set up buttons, fields and working with text in livecode. I smacked it up in a week. This game editor creates an array for my game and stores it to a text file. What I do then is to build the "player" of my game in AppGameKit - Because AppGameKit is much better to make a game with. Then I import the text file from my editor into the AppGameKit app.
My problem initially was that my AppGameKit app didn't read this text file on the mac, because agk packs all the media files into to app itself when it´s built. What I found out is that I am able to store the array text file from my game editor inside the agk.app by using the following file path :"/users/myusername/AGK Projects/MyAGKappProjectfolder/MyAGKapp.App/Contents/Resources/media/myarray.txt"
The key here is that the "MyAGKapp.app" that agk produces is actually a folder. This is also true of every other ".app" files on the mac. Its usually not advised to write into the application, but since Im the developer, I am the boss.
BUT, if it was possible to create a folder for the agk app under "application support" that the application will use - like other apps in the mac system - then I will be glad if anyone could tell me how.
Tim