cli: add --db_backend and --db_dir flags to tendermint node cmd (#4235)

Fixes #4234

CHANGELOG_PENDING.md

@@ -18,7 +18,7 @@ and a validator address plus a timestamp. Note we may remove the validator
 address & timestamp fields in the future (see ADR-25).
 
 Special thanks to external contributors on this release:
-@erikgrinaker, @PSalant726, @gchaincl, @gregzaitsev
+@erikgrinaker, @PSalant726, @gchaincl, @gregzaitsev, @princesinha19
 
 Friendly reminder, we have a [bug bounty
 program](https://hackerone.com/tendermint).
@@ -96,6 +96,7 @@ program](https://hackerone.com/tendermint).
 ### FEATURES:
 
 - [p2p] \#4053 Add `unconditional_peer_ids` and `persistent_peers_max_dial_period` config variables (see ADR-050) (@dongsam)
+- [cli] \#4234 Add `--db_backend and --db_dir` flags (@princesinha19)
 
 ### IMPROVEMENTS:
 
@@ -108,6 +109,7 @@ program](https://hackerone.com/tendermint).
 - [crypto] [\#4190](https://github.com/tendermint/tendermint/pull/4190) Added SR25519 signature scheme
 - [abci] \#4177 kvstore: Return `LastBlockHeight` and `LastBlockAppHash` in `Info` (@princesinha19)
 
+
 ### BUG FIXES:
 
 - [rpc/lib][\#4051](https://github.com/tendermint/tendermint/pull/4131) Fix RPC client, which was previously resolving https protocol to http (@yenkhoon)

cmd/tendermint/commands/run_node.go

@@ -65,6 +65,16 @@ func AddNodeFlags(cmd *cobra.Command) {
 		"consensus.create_empty_blocks_interval",
 		string(config.Consensus.CreateEmptyBlocksInterval),
 		"The possible interval between empty blocks")
+
+	// db flags
+	cmd.Flags().String(
+		"db_backend",
+		config.DBBackend,
+		"Database backend: goleveldb | cleveldb | boltdb")
+	cmd.Flags().String(
+		"db_dir",
+		config.DBPath,
+		"Database directory")
 }
 
 // NewRunNodeCmd returns the command that allows the CLI to start a node.