It means that Christ put St. Peter in charge of His Sheepfold:

Lutero:

What the RC translation for the "keys" means the magesterium can make up any dogma they want to.

No. It means that Christ put St. Peter in charge of His Sheepfold:
John 21:17

King James Version (KJV)
¹⁷ He saith unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said unto him, Lord, thou knowest all things; thou knowest that I love thee. Jesus saith unto him, Feed my sheep.