Update README.md

README.md

@@ -1,2 +1,45 @@
 # mill-caliban
-Caliban codegen plugin for Mill
+[Caliban](https://github.com/ghostdogpr/caliban) codegen plugin for Mill, ported from Caliban's [codegen-sbt](https://github.com/ghostdogpr/caliban/tree/series/2.x/codegen-sbt/src).
+
+## Installation
+
+```scala
+import $ivy.`io.github.hoangmaihuy::mill-caliban::<latest-version>`
+
+import mill._
+import mill.scalalib._
+import io.github.hoangmaihuy.mill.caliban._
+import caliban.tools.Codegen
+
+object codegen extends ScalaModule with CalibanSourceGenModule {
+
+  override def scalaVersion = "3.3.1"
+
+  override def ivyDeps = super.ivyDeps() ++ Agg(
+    ivy"com.github.ghostdogpr::caliban-client:${CalibanBuildInfo.calibanVersion}"
+  )
+
+  // Optional configurations, below examples are taken from itest build.sc
+  override def calibanFileSettings = Seq(
+    // Explicitly constrain to disambiguate
+    CalibanFileSettings.forFile(os.rel / "schema.graphql")(
+      _.clientName("Client")
+    ),
+    // Another entry for the same file, which will cause another generator to run
+    CalibanFileSettings.forFile(os.rel / "schema.graphql")(
+      _.genType(Codegen.GenType.Schema)
+        .scalarMapping("Json" -> "String")
+        .effect("scala.util.Try")
+        .addDerives(false)
+    ),
+    CalibanFileSettings.forFile(os.rel / "genview" / "schema.graphql")(
+      _.clientName("Client").packageName("genview").genView(true)
+    )
+  )
+
+}
+```
+
+## Licenses
+
+This software is released under the Apache License 2.0. More information in the file LICENSE distributed with this project.