Adds precommit hook for prettier.

Author: ashfurrow

package.json

@@ -38,7 +38,8 @@
     "test": "npm run type-check && jest",
     "type-check": "tsc --noEmit --pretty",
     "prettier": "prettier --write '{src,types}/**/*.ts'",
-    "sync-fixtures": "rsync -avh --delete --stats --progress ../relay/packages/relay-compiler/language/javascript/__tests__/fixtures/flow-generator/*.graphql test/fixtures/type-generator"
+    "sync-fixtures": "rsync -avh --delete --stats --progress ../relay/packages/relay-compiler/language/javascript/__tests__/fixtures/flow-generator/*.graphql test/fixtures/type-generator",
+    "precommit": "lint-staged"
   },
   "dependencies": {
     "immutable": "^3.7.6",
@@ -60,7 +61,9 @@
     "@types/node": "8.5.7",
     "@types/relay-runtime": "^1.3.1",
     "graphql": "^0.13.2",
+    "husky": "^1.1.0",
     "jest": "^22.1.4",
+    "lint-staged": "^7.3.0",
     "prettier": "^1.10.2",
     "relay-compiler": "https://github.com/alloy/relay/releases/download/v1.6.1-plugin.1/relay-compiler-1.6.1-plugin.1.tgz",
     "relay-runtime": "https://github.com/alloy/relay/releases/download/v1.6.1-plugin.1/relay-runtime-1.6.1-plugin.1.tgz",
@@ -84,5 +87,11 @@
       "ts",
       "tsx"
     ]
+  },
+  "lint-staged": {
+    "{src,types}/**/*.ts": [
+      "prettier --write",
+      "git add"
+    ]
   }
 }