Fix contact form POST routing and bake env into build

- nginx: route POST /contact/ to contact.php, GET to router.php
- Dockerfile: COPY .env into image
- entrypoint.sh: source .env on container start
- .dockerignore: allow .env to be included in build context

infra/entrypoint.sh

@@ -1,5 +1,8 @@
 #!/bin/sh
 set -e
+if [ -f /var/www/html/.env ]; then
+    set -a; . /var/www/html/.env; set +a
+fi
 if [ -z "$ALTCHA_HMAC_KEY" ]; then
     export ALTCHA_HMAC_KEY="$(openssl rand -hex 32)"
     echo "Generated ALTCHA_HMAC_KEY" >&2

infra/nginx.conf

@@ -81,8 +81,14 @@ http {
             limit_req zone=contact_limit burst=3 nodelay;
             limit_req_status 429;
             include fastcgi_params;
-            fastcgi_param SCRIPT_FILENAME /var/www/html/src/api/router.php;
-            fastcgi_param QUERY_STRING    type=page&slug=contact;
+            set $contact_script /var/www/html/src/api/router.php;
+            set $contact_query  "type=page&slug=contact";
+            if ($request_method = POST) {
+                set $contact_script /var/www/html/src/api/contact.php;
+                set $contact_query  "";
+            }
+            fastcgi_param SCRIPT_FILENAME $contact_script;
+            fastcgi_param QUERY_STRING    $contact_query;
             fastcgi_pass  127.0.0.1:9000;
         }