doc/md: a detailed tutorial on the gRPC integration (#1663)

doc/md/tutorial-grpc-setting-up.md

@@ -0,0 +1,88 @@
+---
+id: grpc-setting-up
+title: Setting Up
+sidebar_label: Setting Up 
+---
+
+Let's start by initializing a new Go module for our project:
+
+```console
+mkdir ent-grpc-example
+cd ent-grpc-example
+go mod init ent-grpc-example
+```
+
+Next, we use `go run` to invoke the ent code generator to initialize a schema:
+
+```console
+go run -mod=mod entgo.io/ent/cmd/ent init User
+```
+
+Our directory should now look like:
+
+```console
+.
+├── ent
+│   ├── generate.go
+│   └── schema
+│       └── user.go
+├── go.mod
+└── go.sum
+```
+
+Next, let's add the `entproto` package to our project:
+
+```console
+go get -u entgo.io/contrib/entproto
+```
+
+Next, we will define the schema for the `User` entity. Open `ent/schema/user.go` and edit:
+
+```go
+package schema
+
+import (
+	"entgo.io/ent"
+	"entgo.io/ent/schema"
+)
+
+// User holds the schema definition for the User entity.
+type User struct {
+	ent.Schema
+}
+
+// Fields of the User.
+func (User) Fields() []ent.Field {
+	return []ent.Field{
+		field.String("name").
+			Unique(),
+		field.String("email_address").
+			Unique(),
+	}
+}
+```
+
+In this step, we added two unique fields to our `User` entity: `name` and `email_address`. The `ent.Schema` is just the definition of the schema. To create usable production code from it we need to run Ent's code generation tool on it. Run:
+
+```console
+go generate ./...
+```
+
+Notice that new files were created from our schema definition:
+
+```console
+├── ent
+│   ├── client.go
+│   ├── config.go
+// .... many more
+│   ├── user
+│   ├── user.go
+│   ├── user_create.go
+│   ├── user_delete.go
+│   ├── user_query.go
+│   └── user_update.go
+├── go.mod
+└── go.sum
+```
+
+At this point, we can open a connection to a database, run a migration to create the `users` table, and start reading and writing data to it. This is covered on the [Setup Tutorial](tutorial-setup.md), so let's cut to the chase and learn about generating Protobuf definitions and gRPC servers from our schema.