fix: Update nginx config to use dynamic DNS resolution

- Replace upstream blocks with resolver directive
- Use variables for backend addresses to avoid startup errors
- Simplify configuration with single server block
- Add health check endpoint

server/api/node_modules/append-field/index.js

@@ -0,0 +1,12 @@
+var parsePath = require('./lib/parse-path')
+var setValue = require('./lib/set-value')
+
+function appendField (store, key, value) {
+  var steps = parsePath(key)
+
+  steps.reduce(function (context, step) {
+    return setValue(context, step, context[step.key], value)
+  }, store)
+}
+
+module.exports = appendField