Give sudo access to only a particular command

Make a new group, web (call it what you wish)
 
sudo addgroup web
Add your developer(s) to the web group (use their login name).
 
sudo usermod -a -G web your_developer(s)
Then run sudo visudo
 
Add in a line
 
%web ALL=(ALL) /usr/bin/service apache2 *
The developers can then run
 
sudo service apache2 *