intro: add installation step (#1)

* add installation step

* fix: use console tag

* chore: ignore mdbook installation error

Makefile

@@ -4,8 +4,11 @@ help: ## Show this help.
 	@awk 'BEGIN {FS = ":.*?## "} /^[a-zA-Z_-]+:.*?## / {sub("\\\\n",sprintf("\n%22c"," "), $$2);printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}' $(MAKEFILE_LIST)
 
 build: ## Build the book directory
-	@cargo install mdbook
+	@cargo install mdbook || true
 	@mdbook build
 
+test:
+	@mdbook test
+
 deploy: build ## Deploy the site using Netlify's CLI
 	@netlify deploy --prod

src/1_introduction.md

@@ -7,3 +7,19 @@ We assume familiarity with Ethereum's mechanics such as:
 * Deploying a contract & interacting with it
 * Sending funds across accounts
 * Signing messages and recovering their sender
+
+## Installing Ethers-rs
+
+First create a new Rust project:
+
+```console
+$ cargo new ethers-hello-world && cd ethers-hello-world
+```
+
+Edit your `Cargo.toml` and insert the following dependency:
+
+```toml
+[dependencies]
+
+ethers = { git = "https://github.com/gakonst/ethers-rs" }
+```