#Possibly easier but untested method:
wget -O - http://nginx.org/keys/nginx_signing.key | sudo apt-key add -

#Now open ` /etc/apt/sources.list ` and add following repositories at the end

deb http://nginx.org/packages/ubuntu/ trusty nginx
deb-src http://nginx.org/packages/ubuntu/ trusty nginx


## Tested method to install the latest version of nginx ##

#Install the PCRE library needed by nginx
sudo apt-get install libpcre3 libpcre3-dev

#Replace by the latest version number found on http://nginx.org/
wget http://nginx.org/download/nginx-1.7.4.tar.gz

tar -xvf nginx-1.7.4.tar.gz

cd nginx-1.7.4

#These flags make sure to put nginx somewhere that is usuall in PATH and to activate the https module
./configure --sbin-path=/usr/local/sbin --with-http_ssl_module

make

sudo make install

# Download nginx startup script
wget -O init-deb.sh http://library.linode.com/assets/660-init-deb.sh

# Move the script to the init.d directory & make executable
sudo mv init-deb.sh /etc/init.d/nginx
sudo chmod +x /etc/init.d/nginx

# Add nginx to the system startup
sudo /usr/sbin/update-rc.d -f nginx defaults

## Make sure to add the nginx.conf into /etc/init/nginx.conf

#This will make sure you get the following commands
#sudo service nginx start
#sudo service nginx stop
#sudo service nginx restart
#sudo service nginx status