Add Chronicle to Oracles list

docs/tools/Oracle Providers/chronicle.md

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+---
+title: Chronicle
+description: Chronicle enables access to decentralized, scalable, and cost-efficient Oracles.
+keywords: [chronicle, oracle, data feeds, price feeds]
+---
+
+# Chronicle  
+
+[Chronicle Protocol](https://chroniclelabs.org/) is a novel Oracle solution that has exclusively secured over $10B in assets for MakerDAO and its ecosystem since 2017. Chronicle overcomes the current limitations of transferring data on-chain by developing scalable, cost-efficient, decentralized, and verifiable Oracles, rewriting the rulebook on data transparency and accessibility.
+
+### Querying the price of GNO using Chronicle
+Chronicle contracts are read-protected by a whitelist, meaning you won't be able to read them on-chain without your address being added to the whitelist. On the Testnet, users can add themselves to the whitelist through the SelfKisser contract, a process playfully referred to as "kissing" themselves. For access to production Oracles on the Mainnet, please open a support ticket on [Discord](https://discord.com/invite/CjgvJ9EspJ) in the 🆘｜support channel.
+
+For the deployment addresses, please check out the [Dashboard](https://chroniclelabs.org/dashboard/oracles). 
+```solidity
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.16;
+
+/**
+ * @title OracleReader
+ * @notice A simple contract to read from Chronicle oracles
+ * @dev To see the full repository, visit https://github.com/chronicleprotocol/OracleReader-Example.
+ * @dev Addresses in this contract are hardcoded for Gnosis.
+ * For other supported networks, check the https://chroniclelabs.org/dashboard/oracles.
+ */
+contract OracleReader {
+    /**
+    * @notice The Chronicle oracle to read from.
+    * GNO/USD - Chronicle_GNO_USD_2 - 0xBcC6BFFde7888A3008f17c88D5a5e5F0D7462cf9
+    * Network: Gnosis
+    */
+
+    IChronicle public chronicle = IChronicle(address(0xBcC6BFFde7888A3008f17c88D5a5e5F0D7462cf9));
+
+    /** 
+    * @notice The SelfKisser granting access to Chronicle oracles.
+    * SelfKisser_1:0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d
+    * Network: Gnosis
+    */
+    ISelfKisser public selfKisser = ISelfKisser(address(0x0Dcc19657007713483A5cA76e6A7bbe5f56EA37d));
+
+    constructor() {
+        // Note to add address(this) to chronicle oracle's whitelist.
+        // This allows the contract to read from the chronicle oracle.
+        selfKisser.selfKiss(address(chronicle));
+    }
+
+    /** 
+    * @notice Function to read the latest data from the Chronicle oracle.
+    * @return val The current value returned by the oracle.
+    * @return age The timestamp of the last update from the oracle.
+    */
+    function read() external view returns (uint256 val, uint256 age) {
+        (val, age) = chronicle.readWithAge();
+    }
+}
+
+// Copied from [chronicle-std](https://github.com/chronicleprotocol/chronicle-std/blob/main/src/IChronicle.sol).
+interface IChronicle {
+    /** 
+    * @notice Returns the oracle's current value.
+    * @dev Reverts if no value set.
+    * @return value The oracle's current value.
+    */
+    function read() external view returns (uint256 value);
+
+    /** 
+    * @notice Returns the oracle's current value and its age.
+    * @dev Reverts if no value set.
+    * @return value The oracle's current value using 18 decimals places.
+    * @return age The value's age as a Unix Timestamp .
+    * */
+    function readWithAge() external view returns (uint256 value, uint256 age);
+}
+
+// Copied from [self-kisser](https://github.com/chronicleprotocol/self-kisser/blob/main/src/ISelfKisser.sol).
+interface ISelfKisser {
+    /// @notice Kisses caller on oracle `oracle`.
+    function selfKiss(address oracle) external;
+}
+```
+### More examples
+For more examples on integrating Chronicle Oracles, please check the [documentation portal](https://docs.chroniclelabs.org/). 
+
+### Get in touch
+
+If you have any questions or need support, drop us a message on [Discord](https://discord.com/invite/CjgvJ9EspJ).
+