docs: update integration docs to include light client registration. (#…

…2905)

docs/ibc/integration.md

@@ -28,7 +28,23 @@ The first step is to add the following modules to the `BasicManager`: `x/capabil
 and `x/ibc-transfer`. After that, we need to grant `Minter` and `Burner` permissions to
 the `ibc-transfer` `ModuleAccount` to mint and burn relayed tokens.
 
+### Integrating Light Clients
+
+> Note that from v7 onwards, all light clients have to be explicitly registered in a chain's app.go and follow the steps listed below. 
+  This is in contrast to earlier versions of ibc-go when 07-tendermint and 06-solomachine were added out of the box.
+
+All light clients must be registered with `module.BasicManager` in a chain's app.go file.
+
+The following code example shows how to register the existing `ibctm.AppModuleBasic{}` light client implementation.
+
 ```go
+
+import (
+    ...
+    ibctm "github.com/cosmos/ibc-go/v6/modules/light-clients/07-tendermint"
+    ...
+)
+
 // app.go
 var (
 
@@ -37,6 +53,9 @@ var (
     capability.AppModuleBasic{},
     ibc.AppModuleBasic{},
     transfer.AppModuleBasic{}, // i.e ibc-transfer module
+
+    // register light clients on IBC
+    ibctm.AppModuleBasic{},
   )
 
   // module account permissions