All Matlab codes should be posted here, I dont believe you can upload files but you can copy your m-file and paste it here. Click the '+' button to create a new file, give it a name and paste the code then click the green commit button. Make sure your code is commented properly. In the end we will compile everything into one program.
There is also version control on this so if you make changes to a file you can go back in time and see the previous content. Dont share this with anyone :)