Add rust chapter

docs/tutorial/rust.md

@@ -0,0 +1,57 @@
+---
+sidebar_position: 6
+---
+
+# Writing and Calling a Rust Contract
+
+One of the benefits of using PolkaVM vs EVM is that you can write contracts
+in any language that compile down to RISC-V. In this chapter we learn how
+to use Rust to write a contract and how to call it from Solidity.
+
+## Use the Rust Template
+
+[Here](https://github.com/paritytech/rust-contract-template) you can find our
+Rust contract template. You can [make use](https://docs.github.com/en/repositories/creating-and-managing-repositories/creating-a-repository-from-a-template#creating-a-repository-from-a-template)
+of githubs template feature in order to  make it the starting point of your own repository.
+
+## Compile the template
+
+Simply follow the README inside the template to learn how to compile the project into a
+`contract.polkavm`. The repository also contains a example Solidity file that demonstrates
+how to call this contract.
+
+## Deploy the template
+
+You can use ether.js to deploy the Rust contract. We [covered that](/getting-started-with-ethers.js#deploy-a-contract)
+earlier in the tutorial. You skip the compilation step and pass the raw `contract.polkavm` as bytecode:
+
+```ts
+import { ContractFactory } from 'ethers'
+
+/// We specify the abi manually since the Rust compiler won't generate one for us
+const abi = ["constructor()", "function fibonacci(uint) view returns(uint)"];
+const bytecode = readFileSync('contract.polkavm');
+
+// Instantiate a contract factory.
+const contractFactory = new ContractFactory(abi, bytecode, signer)
+
+try {
+  const contract = await contractFactory.deploy(/* args */)
+  await contract.waitForDeployment()
+
+  // Get the contract's address.
+  const address = await contract.getAddress()
+  console.log(`Contract deployed: ${address}`)
+} catch (e) {
+  console.error('Failed to deploy contract', e)
+}
+
+// Try calling the fibonacci function directly
+// ...
+```
+
+## Deploy and Use the Caller Contract
+
+You can now deploy the [Solidity contract](https://github.com/paritytech/rust-contract-template/blob/master/call_from_sol.sol)
+from the template repository using ether.js or REMIX. It is setup to call the Rust contract via the
+`fibonacciRust` function. You need to pass the address from the previous step.