Can not "brew install postgresql"

Question

I cannot install postgresql with homebrew.

$ brew install postgresql
Error: Could not create /usr/local/Cellar
Check you have permission to write to /usr/local

I am not sure if homebrew was installed well. If you need more information, I will update this.

Answer 1

I created /usr/local/Cellar by myself, then could install successfully.

Answer 2

I find that if I get this problem with brew I just fix the permissions on the /use/local folder:

sudo chown -R $(whoami):admin /usr/local