Sourcing an alias file in oh my zsh custom/ folder

My understanding is that you are trying to add your custom file aliases.zsh to the directory .oh-my-zsh/custom/

I just did this and tried using one of the aliases I defined in the file and it worked. Just make sure you restart your terminal's session and have the correct alias formatting alias zshconfig="mate ~/.zshrc"

You should just symlink your main file in the custom dir.

ln -s ~/.aliases ~/.oh-my-zsh/custom/aliases.zsh