docs(rosetta): add Rosetta documentation page

docs/README.md

@@ -66,6 +66,7 @@ aside: false
 - **[Specifications](./spec/)**: Specifications of modules and other parts of the Cosmos SDK.
 - **[SDK API Reference](https://godoc.org/github.com/cosmos/cosmos-sdk)**: Godocs of the Cosmos SDK.
 - **[REST and RPC Endpoints](https://cosmos.network/rpc/)**: List of endpoints to interact with a `gaia` full-node.
+- **[Rosetta API](./run-node/rosetta.md)**: Rosetta API integration.
 
 ## Cosmos Hub
 

docs/run-node/rosetta.md

@@ -4,16 +4,66 @@ order: 6
 
 # Rosetta
 
-Package rosetta implements the rosetta API for the current cosmos sdk release series.
+The `rosetta` package implements Coinbase's [Rosetta API](https://www.rosetta-api.org). This document provides instructions on how to use the Rosetta API integration. For information about the motivation and design choices, refer to [ADR 035](../architecture/adr-035-rosetta-api-support.md).
 
-## Extension
+## Add Rosetta Command
+
+The Rosetta API server is a stand-alone server that connects to a node of a chain developed with Cosmos SDK. 
+
+To enable Rosetta API support, it's required to add the `RosettaCommand` to your application's root command file (e.g. `appd/cmd/root.go`).
+
+Import the `server` package:
+
+```go
+    "github.com/cosmos/cosmos-sdk/server"
+```
+
+Find the following line:
+
+```go
+initRootCmd(rootCmd, encodingConfig)
+```
+
+After that line, add the following:
+
+```go
+rootCmd.AddCommand(
+  server.RosettaCommand(encodingConfig.InterfaceRegistry, encodingConfig.Marshaler)
+)
+```
+
+The `RosettaCommand` function builds the `rosetta` root command and is defined in the `server` package within Cosmos SDK.
+
+Since we’ve updated the Cosmos SDK to work with the Rosetta API, updating the application's root command file is all you need to do.
+
+An implementation example can be found in `simapp` package.
+
+## Use Rosetta Command
+
+To run Rosetta in your application CLI, use the following command:
+
+```
+appd rosetta --help
+```
+
+To test and run Rosetta API endpoints for applications that are running and exposed, use the following command:
+
+```
+appd rosetta
+     --blockchain "your application name (ex: gaia)"
+     --network "your chain identifier (ex: testnet-1)"
+     --tendermint "tendermint endpoint (ex: localhost:26657)"
+     --grpc "gRPC endpoint (ex: localhost:9090)"
+     --addr "rosetta binding address (ex: :8080)"
+```
+
+## Extensions
 
 There are two ways in which you can customize and extend the implementation with your custom settings.
 
 ### Message extension
 
-In order to make an `sdk.Msg` understandable by rosetta the only thing which is required is adding the methods to your message that satisfy the `rosetta.Msg` interface.
-Examples on how to do so can be found in the staking types such as `MsgDelegate`, or in bank types such as `MsgSend`.
+In order to make an `sdk.Msg` understandable by rosetta the only thing which is required is adding the methods to your messages that satisfy the `rosetta.Msg` interface. Examples on how to do so can be found in the staking types such as `MsgDelegate`, or in bank types such as `MsgSend`.
 
 ### Client interface override
 
@@ -43,6 +93,8 @@ func (c *CustomClient) ConstructionPayload(_ context.Context, request *types.Con
 }
 ```
 
+NOTE: when using a customized client, the command cannot be used as the constructors required **may** differ, so it's required to create a new one. We intend to provide a way to init a customized client without writing extra code in the future.
+
 ### Error extension
 
 Since rosetta requires to provide 'returned' errors to network options. In order to declare a new rosetta error, we use the `errors` package in cosmos-rosetta-gateway.
@@ -58,29 +110,3 @@ var CustomError = crgerrs.RegisterError(100, "custom message", customErrRetriabl
 ```
 
 Note: errors must be registered before cosmos-rosetta-gateway's `Server`.`Start` method is called. Otherwise the registration will be ignored. Errors with same code will be ignored too.
-
-## Integration in app.go
-
-To integrate rosetta as a command in your application, in app.go, in your root command simply use the `server.RosettaCommand` method.
-
-Example:
-
-```go
-package app
-import (
-
-"github.com/cosmos/cosmos-sdk/server"
-"github.com/spf13/cobra"
-)
-
-func buildAppCommand(rootCmd *cobra.Command) {
-    // more app.go init stuff
-	// ...
-    // add rosetta command
-	rootCmd.AddCommand(server.RosettaCommand(encodingConfig.InterfaceRegistry, encodingConfig.Marshaler))
-}
-```
-
-A full implementation example can be found in `simapp` package.
-
-NOTE: when using a customized client, the command cannot be used as the constructors required **may** differ, so it's required to create a new one. We intend to provide a way to init a customized client without writing extra code in the future.