nginx: Add check_role function to worker init

hosts/architect/nginx.nix

@@ -47,6 +47,22 @@
 
       # https://github.com/openresty/lua-resty-redis/issues/159
       resolver local=on ipv6=off;
+
+      init_worker_by_lua_block {
+      function check_role (res, role)
+        if res.user.roles == nil then
+          return false
+        end
+
+        for _,v in pairs(res.user.roles) do
+          if string.lower(v) == role then
+            return true
+          end
+        end
+
+        return false
+        end
+      }
     '';
 
     appendConfig = ''