diff --git a/Dockerfile b/Dockerfile
index 2002154..06c09cc 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,8 +3,7 @@ FROM node:12-alpine
 WORKDIR /excalidraw-room
 
 COPY package.json yarn.lock ./
-COPY scripts ./scripts
-RUN SKIP_YARN_POSTINSTALL=true yarn
+RUN yarn
 
 COPY tsconfig.json ./
 COPY src ./src
diff --git a/package.json b/package.json
index 12292e4..a6195e2 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,6 @@
     "build": "tsc",
     "fix": "yarn prettier --write",
     "lint": "yarn prettier --list-different",
-    "postinstall": "node scripts/postinstall.js",
     "prettier": "prettier \"**/*.{ts,md,json,yaml,yml}\"",
     "start": "node dist/index.js",
     "test": "yarn lint"
@@ -40,9 +39,6 @@
     "typescript": "3.9.5"
   },
   "eslintConfig": {
-    "env": {
-      "es6": true
-    },
     "extends": [
       "prettier"
     ],
diff --git a/scripts/postinstall.js b/scripts/postinstall.js
deleted file mode 100644
index 0ca5207..0000000
--- a/scripts/postinstall.js
+++ /dev/null
@@ -1,16 +0,0 @@
-// This allows `postinstall` to be skipped via `SKIP_YARN_POSTINSTALL=true`.
-// This is useful when building a Docker image because it lets you
-// take advantage of cached Docker layers and run Yarn
-// only if `package.json` or `yarn.lock` changed,
-// and not every time source code is updated:
-// https://nodejs.org/en/docs/guides/nodejs-docker-webapp/
-//
-// However, there doesn't appear to be a way to skip `postinstall`,
-// and doing `yarn --ignore-scripts` could prevent native packages from building:
-// https://github.com/yarnpkg/yarn/issues/4100
-
-const { execSync } = require("child_process");
-
-if (process.env.SKIP_YARN_POSTINSTALL !== "true") {
-  execSync("yarnpkg build", { stdio: "inherit" });
-}
diff --git a/tsconfig.json b/tsconfig.json
index 54b76ae..a239fb1 100755
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -12,6 +12,5 @@
     "resolveJsonModule": true,
     "isolatedModules": true,
     "outDir": "dist"
-  },
-  "include": ["src/**/*"]
+  }
 }