Add setup instructions

README.md

@@ -1 +1,31 @@
-# sbt-bundlemon
+# sbt-bundlemon
+
+Track Scala.js bundle size in CI with [BundleMon](https://github.com/LironEr/bundlemon). Check out an [example PR](https://github.com/armanbilge/sbt-bundlemon/pull/2#issuecomment-1187659884).
+
+## Configure
+
+1. Install the [BundleMon App](https://github.com/apps/bundlemon) on your repository.
+
+2. In `project/plugins.sbt` add:
+```scala
+addSbtPlugin("com.armanbilge" % "sbt-bundlemon" % "0.1.0")
+```
+
+3. Enable the plugin on one or more _applications_ in your `build.sbt` (or anything that [exports to JavaScript](https://www.scala-js.org/doc/interoperability/export-to-javascript.html)):
+```scala
+lazy val todoMvc = project.in(file("todo-mvc"))
+  .enablePlugins(BundleMonPlugin)
+  .settings(
+    scalaJSUseMainModuleInitializer := true
+  )
+```
+
+4. Add the following step to step to your CI workflow:
+```yaml
+- name: Monitor bundle size
+  run: sbt bundleMon
+```
+
+5. Now you will get reports about the gzipped, fully-optimized bundle size in CI status and PR comments!
+
+Please open issues and PRs for anything and everything :)