Fix .gitignore: stop tracking ignored files

backend/lib/openzeppelin-contracts/contracts/token/ERC1155/presets/ERC1155PresetMinterPauser.sol

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+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC1155/presets/ERC1155PresetMinterPauser.sol)
+
+pragma solidity ^0.8.0;
+
+import "../ERC1155.sol";
+import "../extensions/ERC1155Burnable.sol";
+import "../extensions/ERC1155Pausable.sol";
+import "../../../access/AccessControlEnumerable.sol";
+import "../../../utils/Context.sol";
+
+/**
+ * @dev {ERC1155} token, including:
+ *
+ *  - ability for holders to burn (destroy) their tokens
+ *  - a minter role that allows for token minting (creation)
+ *  - a pauser role that allows to stop all token transfers
+ *
+ * This contract uses {AccessControl} to lock permissioned functions using the
+ * different roles - head to its documentation for details.
+ *
+ * The account that deploys the contract will be granted the minter and pauser
+ * roles, as well as the default admin role, which will let it grant both minter
+ * and pauser roles to other accounts.
+ *
+ * _Deprecated in favor of https://wizard.openzeppelin.com/[Contracts Wizard]._
+ */
+contract ERC1155PresetMinterPauser is Context, AccessControlEnumerable, ERC1155Burnable, ERC1155Pausable {
+    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
+    bytes32 public constant PAUSER_ROLE = keccak256("PAUSER_ROLE");
+
+    /**
+     * @dev Grants `DEFAULT_ADMIN_ROLE`, `MINTER_ROLE`, and `PAUSER_ROLE` to the account that
+     * deploys the contract.
+     */
+    constructor(string memory uri) ERC1155(uri) {
+        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
+
+        _setupRole(MINTER_ROLE, _msgSender());
+        _setupRole(PAUSER_ROLE, _msgSender());
+    }
+
+    /**
+     * @dev Creates `amount` new tokens for `to`, of token type `id`.
+     *
+     * See {ERC1155-_mint}.
+     *
+     * Requirements:
+     *
+     * - the caller must have the `MINTER_ROLE`.
+     */
+    function mint(address to, uint256 id, uint256 amount, bytes memory data) public virtual {
+        require(hasRole(MINTER_ROLE, _msgSender()), "ERC1155PresetMinterPauser: must have minter role to mint");
+
+        _mint(to, id, amount, data);
+    }
+
+    /**
+     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] variant of {mint}.
+     */
+    function mintBatch(address to, uint256[] memory ids, uint256[] memory amounts, bytes memory data) public virtual {
+        require(hasRole(MINTER_ROLE, _msgSender()), "ERC1155PresetMinterPauser: must have minter role to mint");
+
+        _mintBatch(to, ids, amounts, data);
+    }
+
+    /**
+     * @dev Pauses all token transfers.
+     *
+     * See {ERC1155Pausable} and {Pausable-_pause}.
+     *
+     * Requirements:
+     *
+     * - the caller must have the `PAUSER_ROLE`.
+     */
+    function pause() public virtual {
+        require(hasRole(PAUSER_ROLE, _msgSender()), "ERC1155PresetMinterPauser: must have pauser role to pause");
+        _pause();
+    }
+
+    /**
+     * @dev Unpauses all token transfers.
+     *
+     * See {ERC1155Pausable} and {Pausable-_unpause}.
+     *
+     * Requirements:
+     *
+     * - the caller must have the `PAUSER_ROLE`.
+     */
+    function unpause() public virtual {
+        require(hasRole(PAUSER_ROLE, _msgSender()), "ERC1155PresetMinterPauser: must have pauser role to unpause");
+        _unpause();
+    }
+
+    /**
+     * @dev See {IERC165-supportsInterface}.
+     */
+    function supportsInterface(
+        bytes4 interfaceId
+    ) public view virtual override(AccessControlEnumerable, ERC1155) returns (bool) {
+        return super.supportsInterface(interfaceId);
+    }
+
+    function _beforeTokenTransfer(
+        address operator,
+        address from,
+        address to,
+        uint256[] memory ids,
+        uint256[] memory amounts,
+        bytes memory data
+    ) internal virtual override(ERC1155, ERC1155Pausable) {
+        super._beforeTokenTransfer(operator, from, to, ids, amounts, data);
+    }
+}

backend/lib/openzeppelin-contracts/contracts/token/ERC1155/presets/README.md

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+Contract presets are now deprecated in favor of [Contracts Wizard](https://wizard.openzeppelin.com/) as a more powerful alternative.