Fix for the --home flag (#852)

* Adds the necessary setup to the gaia viper root to handle the home flag and config.toml file correctly

* Add an environment variable prefix.

cmd/gaiad/cmd/root.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/baseapp"
 	"github.com/cosmos/cosmos-sdk/client"
+	config "github.com/cosmos/cosmos-sdk/client/config"
 	"github.com/cosmos/cosmos-sdk/client/debug"
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	"github.com/cosmos/cosmos-sdk/client/keys"
@@ -22,14 +23,13 @@ import (
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	"github.com/cosmos/cosmos-sdk/x/crisis"
 	genutilcli "github.com/cosmos/cosmos-sdk/x/genutil/client/cli"
+	gaia "github.com/cosmos/gaia/v4/app"
+	"github.com/cosmos/gaia/v4/app/params"
 	"github.com/spf13/cast"
 	"github.com/spf13/cobra"
 	tmcli "github.com/tendermint/tendermint/libs/cli"
 	"github.com/tendermint/tendermint/libs/log"
 	dbm "github.com/tendermint/tm-db"
-
-	gaia "github.com/cosmos/gaia/v4/app"
-	"github.com/cosmos/gaia/v4/app/params"
 )
 
 // NewRootCmd creates a new root command for simd. It is called once in the
@@ -44,12 +44,24 @@ func NewRootCmd() (*cobra.Command, params.EncodingConfig) {
 		WithInput(os.Stdin).
 		WithAccountRetriever(types.AccountRetriever{}).
 		WithBroadcastMode(flags.BroadcastBlock).
-		WithHomeDir(gaia.DefaultNodeHome)
+		WithHomeDir(gaia.DefaultNodeHome).
+		WithViper("GAIA")
 
 	rootCmd := &cobra.Command{
 		Use:   "gaiad",
 		Short: "Stargate Cosmos Hub App",
 		PersistentPreRunE: func(cmd *cobra.Command, _ []string) error {
+			// set the default command outputs
+			cmd.SetOut(cmd.OutOrStdout())
+			cmd.SetErr(cmd.ErrOrStderr())
+
+			initClientCtx = client.ReadHomeFlag(initClientCtx, cmd)
+
+			initClientCtx, err := config.ReadFromClientConfig(initClientCtx)
+			if err != nil {
+				return err
+			}
+
 			if err := client.SetCmdClientContextHandler(initClientCtx, cmd); err != nil {
 				return err
 			}