message: move file-loader to devDependencies
diff: "chalk": "^1.1.3",
  "compression": "^1.6.2",
  "express": "^4.15.2",
  - "file-loader": "^0.11.1",
  "helmet": "^3.5.0",
  "history": "^4.6.1",
  "hpp": "^0.2.2",
  "eslint-plugin-jsx-a11y": "^4.0.0",
  "eslint-plugin-react": "^6.10.3",
  "extract-text-webpack-plugin": "^2.1.0",
  + "file-loader": "^0.11.1",
  "flow-bin": "0.44.2",
  "image-webpack-loader": "^3.3.0",
  "imports-loader": "^0.7.1",
  