nginx reverse proxy sending links in http

I have an nginx reverse proxy running based on the working setup here. It is sending the page to our backend (apache) correctly except the page comes back with all links in http (page itself is https). I know that the configuration change needs to be done on the backend (apache), I just don't know where.

Here is my original setup:

    server {
listen 80;
server_name example.com;

rewrite ^(.*) https://$server_name$1 permanent;
 }
    server {
listen 443;
server_name example.com;

root   /var/web/;

ssl                  on;
ssl_certificate /etc/apache2/ssl/server.crt;
ssl_certificate_key /etc/apache2/ssl/server.key;

# ---------------------------------------------
# https://mozilla.github.io/server-side-tls/ssl-config-generator/
# generate with openssl dhparam -out dhparams.pem 2048
ssl_dhparam /etc/apache2/ssl/dhparam.pem;


ssl_prefer_server_ciphers on;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_session_tickets off;

# Diffie-Hellman parameter for DHE ciphersuites, recommended 2048 bits
#ssl_dhparam /etc/pki/nginx/dh2048.pem;

# intermediate configuration. tweak to your needs.
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:ECDHE-RSA-DES-CBC3-SHA:ECDHE-ECDSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA';

location / {
    proxy_pass http://127.0.0.1:8080;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto https;
}

}

Apache config

    <VirtualHost *:8080>
    ServerName localhost:8080
    ServerAlias 127.0.0.1:8080
    DocumentRoot /var/web/
    DirectoryIndex index.html index.xhtml
# - absorb the shared virtual host settings
    </VirtualHost>

Use return instead of rewrite.

server {
    listen 80;
    server_name example.com;
    return 301 https://$host$request_uri;
}