fix: stripping /docs in nginx config now handles homepage

While reviewing the new images it was noticed that the docs homepage rendered
with a 404 status code, not a 200. This fixes the nginx config edge-case
specifically related to the homepage and the dropping of `/docs` from the
request URL in nginx

.circleci/config.yml

@@ -146,6 +146,12 @@ jobs:
                 printf '.'
                 sleep 1
             done
+      - run:
+          name: Test nginx /docs rewriting
+          command: |
+            ./bin/assert-success.sh /docs
+            ./bin/assert-redirect.sh /docs/ https://localhost/docs
+            ./bin/assert-success.sh /docs/channels
       - run:
           name: Smoke test quickstart redirects
           command: |

config/nginx.conf.erb

@@ -74,11 +74,12 @@ http {
 
     error_page 404 500 /404.html;
 
-    # Removes trailing slashes everywhere
+    # Removes trailing slashes everywhere (by redirecting)
     rewrite ^/(.*)/$ <%= ENV['SKIP_HTTPS'] == 'true' ? '$scheme' : 'https' %>://$host/$1 permanent;
 
-    # Strip /docs from the requests (we build with --prefix-paths)
-    rewrite ^/docs/(.*)$ /$1;
+    # Strip /docs from the requests (we build with --prefix-paths and our files are in public/)
+    rewrite ^/docs/(.*)$ /$1 last;
+    rewrite ^/docs$ / last;
 
     location ~* \.json$ {
       more_set_headers 'Access-Control-Allow-Origin: *';