STAGING環境でデプロイした時のSSHKit::Command::Failed: git ls-remote git@github.com:velljp/circus-vell.git 解決法

# エラー内容
https://gyazo.com/02b8cf241cc1f370a5635ea6fb236e2c
```
リンクの内容

[cvsys@ip-10-1-0-21 ~]$ sh dist.sh
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
  INFO [c61e9b14] Running rsync -az -e ssh /home/cvsys/.rbenv/ 127.0.0.1:/home/cvsys/.rbenv as cvsys@localhost
 DEBUG [c61e9b14] Command: rsync -az -e ssh /home/cvsys/.rbenv/ 127.0.0.1:/home/cvsys/.rbenv
  INFO [a483de23] Finished in 0.449 seconds with exit status 0 (successful).
  INFO [9dfd5faf] Running rsync -az -e ssh /home/cvsys/.bash_profile 127.0.0.1:/home/cvsys/ as cvsys@localhost
 DEBUG [9dfd5faf] Command: rsync -az -e ssh /home/cvsys/.bash_profile 127.0.0.1:/home/cvsys/
  INFO [903ff29c] Finished in 0.271 seconds with exit status 0 (successful).
 DEBUG [f7dcc0b8] Running [ -d $HOME/.rbenv/versions/2.6.3 ] as cvsys@127.0.0.1
 DEBUG [f7dcc0b8] Command: [ -d $HOME/.rbenv/versions/2.6.3 ]
 DEBUG [cb35cb07] Finished in 0.211 seconds with exit status 0 (successful).
  INFO [b0593ade] Running /usr/bin/env mkdir -p /data/cvsys/circus-vell/shared/config as cvsys@127.0.0.1
 DEBUG [b0593ade] Command: ( export RBENV_ROOT="$HOME/.rbenv" RBENV_VERSION="2.6.3" ; /usr/bin/env mkdir -p /data/cvsys/circus-vell/shared/config )
  INFO [06e444cb] Finished in 0.077 seconds with exit status 0 (successful).
  INFO [f634aa19] Running rsync -az -e ssh shared/config/ 127.0.0.1:/data/cvsys/circus-vell/shared/config as cvsys@localhost
 DEBUG [f634aa19] Command: rsync -az -e ssh shared/config/ 127.0.0.1:/data/cvsys/circus-vell/shared/config
  INFO [faf20864] Finished in 0.195 seconds with exit status 0 (successful).
  INFO [7253404c] Running /usr/bin/env mkdir -p /data/cvsys/log as cvsys@127.0.0.1
 DEBUG [7253404c] Command: ( export RBENV_ROOT="$HOME/.rbenv" RBENV_VERSION="2.6.3" ; /usr/bin/env mkdir -p /data/cvsys/log )
  INFO [4b3e5039] Finished in 0.036 seconds with exit status 0 (successful).
  INFO [64aca33a] Running git ls-remote git@github.com:velljp/circus-vell.git HEAD as cvsys@localhost
 DEBUG [64aca33a] Command: git ls-remote git@github.com:velljp/circus-vell.git HEAD
 DEBUG [43c06e1d] 	Permission denied (publickey).
 DEBUG [43c06e1d] 	fatal: Could not read from remote repository.
 DEBUG [43c06e1d] 	
 DEBUG [43c06e1d] 	Please make sure you have the correct access rights
 DEBUG [43c06e1d] 	and the repository exists.
(Backtrace restricted to imported tasks)
cap aborted!
SSHKit::Command::Failed: git ls-remote git@github.com:velljp/circus-vell.git HEAD exit status: 32768
git ls-remote git@github.com:velljp/circus-vell.git HEAD stdout: Nothing written
git ls-remote git@github.com:velljp/circus-vell.git HEAD stderr: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Tasks: TOP => bundle_rsync:check
(See full trace by running task with --trace)
The deploy has failed with an error: git ls-remote git@github.com:velljp/circus-vell.git HEAD exit status: 32768
git ls-remote git@github.com:velljp/circus-vell.git HEAD stdout: Nothing written
git ls-remote git@github.com:velljp/circus-vell.git HEAD stderr: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
WARNING: Use strings for Figaro configuration. 5495674 was converted to "5495674".
bundle exec ridgepole -c /data/cvsys/circus-vell/releases/20210616070711/config/database.yml -f /data/cvsys/circus-vell/releases/20210616070711/db/schemas/Schemafile --apply -E staging
Apply `/data/cvsys/circus-vell/releases/20210616070711/db/schemas/Schemafile`
No change
```
# 解決法
### ①別ターミナルを開き、以下のコマンドを入力する。
```
ssh-add
```
```
ssh -T git@github.com
```
https://gyazo.com/e633bd9f548c50c223b7983c9e460a4b
### ②STAGINGサーバーのターミナルで再度デプロイする。
```
sh dist.sh
```