shiritori: add firebase.json

Change-Id: I7071578525aeec2cb2663f7212373426742eb95e

Author: proppy

firebase.json

@@ -1 +1,19 @@
-{}
+{
+  "database": {
+    "rules": "database.rules.json"
+  },
+  "functions": {
+    "predeploy": [
+      "npm --prefix $RESOURCE_DIR run lint"
+    ],
+    "source": "functions"
+  },
+  "hosting": {
+    "public": "public",
+    "ignore": [
+      "firebase.json",
+      "**/.*",
+      "**/node_modules/**"
+    ]
+  }
+}