/usr/local/bin is not writable mac

sudo chown -R yourusename:admin /usr/local/bin

Mac-Pro:local user$ brew install imagemagick
 Error: You must `brew link jpeg' before imagemagick can be installed
 Mac-Pro:local user$ brew link jpeg
 Linking /usr/local/Cellar/jpeg/8d... 
 Error: Could not symlink file: /usr/local/Cellar/jpeg/8d/bin/wrjpgcom
 /usr/local/bin is not writable. You should change its permissions.