Draw field on new webpage.

Change-Id: Ibf71aa126e51cb6a6110d890c13d0633fbc3087b
diff --git a/y2020/www/BUILD b/y2020/www/BUILD
index 292618b..e8c227d 100644
--- a/y2020/www/BUILD
+++ b/y2020/www/BUILD
@@ -16,6 +16,18 @@
     ],
 )
 
+ts_library(
+    name = "field_main",
+    srcs = [
+        "field_main.ts",
+        "field_handler.ts",
+        "constants.ts",
+    ],
+    deps = [
+        "//aos/network/www:proxy",
+    ],
+)
+
 rollup_bundle(
     name = "main_bundle",
     entry_point = "y2020/www/main",
@@ -25,6 +37,15 @@
     ],
 )
 
+rollup_bundle(
+    name = "field_main_bundle",
+    entry_point = "y2020/www/field_main",
+    deps = [
+        "field_main",
+    ],
+    visibility = ["//y2020:__subpackages__"],
+)
+
 filegroup(
     name = "files",
     srcs = glob([