Update README.md

Author: scala-steward

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+---
+id: index
+title: "Introduction to ZIO Interop Scalaz"
+sidebar_label: "ZIO Interop Scalaz"
+---
+
+This library provides instances for several Scalaz typeclasses.
+
+@PROJECT_BADGES@
+
+## Installation
+
+In order to use this library, we need to add the following line in our `build.sbt` file:
+
+```scala
+libraryDependencies += "dev.zio" %% "zio-interop-scalaz" % "@VERSION@"
+```
+
+## Example 1
+
+```scala
+import scalaz._, Scalaz._
+import zio.interop.scalaz._
+
+type Database = IList[User]
+
+def findUser(id: UserId): ZIO[Database, UserError, User] = ...
+def findUsers(ids: IList[UserId]): ZIO[Database, UserError, IList[User]] = ids.traverse(findUser(_))
+```
+
+## `ZIO` parallel `Applicative` instance
+
+Due to `Applicative` and `Monad` coherence law `ZIO`'s `Applicative` instance has to be implemented in terms of `bind` hence when composing multiple effects using `Applicative` they will be sequenced. To cope with that limitation `ZIO` tagged with `Parallel` has an `Applicative` instance which is not `Monad` and operates in parallel.
+
+## Example 2
+
+```scala
+import scalaz._, Scalaz._
+import zio.interop.scalaz._
+
+case class Dashboard(details: UserDetails, history: TransactionHistory)
+
+def getDetails(id: UserId): ZIO[Database, UserError, UserDetails] = ...
+def getHistory(id: UserId): ZIO[Database, UserError, TransactionHistory] = ...
+
+def buildDashboard(id: UserId): ZIO[Database, UserError, Dashboard] =
+  Tag.unwrap(^(par(getDetails(id)), par(getHistory(id)))(Dashboard.apply))
+
+def par[R, E, A](io: ZIO[R, E, A]): ParIO[R, E, A] = Tag(io)
+```