add firebase config, update build

.gitignore

@@ -21,3 +21,4 @@
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+*.cache

firebase.json

@@ -1,16 +1,10 @@
 {
   "hosting": {
-    "public": "public",
+    "public": "build",
     "ignore": [
       "firebase.json",
       "**/.*",
       "**/node_modules/**"
-    ],
-    "rewrites": [
-      {
-        "source": "**",
-        "destination": "/index.html"
-      }
     ]
   }
 }