Adding mix slides.

docs/slides.md

@@ -1683,6 +1683,123 @@ Exceptions in the `else` block are not caught. If no pattern inside the `else` b
 ---
 class: center, middle
 
+## Mix
+
+---
+class: center, middle
+
+Mix is a build tool that ships with Elixir that provides tasks for creating, compiling, testing your application, managing its dependencies and much more...
+
+---
+class: center, middle
+
+```bash
+mix new <app_name>
+```
+
+---
+class: center, middle
+
+```bash
+elixir/app/hello $ tree
+.
+├── README.md
+├── lib
+│   └── hello.ex
+├── mix.exs
+└── test
+    ├── hello_test.exs
+    └── test_helper.exs
+
+3 directories, 5 files
+```
+
+---
+class: center, middle
+
+Peeking into the `mix.exs` file
+
+---
+
+- Configures the project using `def project`
+
+- `def application`, which is used to generate an application file.
+
+- a private function named `deps`, which is invoked from the project function, that defines our project dependencies
+
+---
+class: center, middle
+
+This structure is enough to compile our project:
+
+```bash
+mix compile
+```
+
+---
+class: center, middle
+
+Once the project is compiled, you can start a iex session inside the project.
+
+```bash
+iex -S mix
+```
+
+---
+class: center, middle
+
+The `-S mix` is necessary to load the project in the interactive shell.
+
+---
+
+While you may start a new session whenever there are changes to the project source code, you can also recompile the project from within iex with the recompile helper, like this:
+
+```elixir
+recompile()
+```
+
+---
+
+### Other Features
+
+- Auto code formatting via `.formatter.exs` using `mix format`.
+
+- Environment management. By default, Mix understands three environments:
+
+  `:dev` — the one in which Mix tasks (like compile) run by default
+  `:test` — used by mix test
+  `:prod` — the one you will use to run your project in production
+
+- ...
+
+---
+class: center, middle
+
+```elixir
+def project do
+  [
+    ...,
+    start_permanent: Mix.env() == :prod,
+    ...
+  ]
+end
+```
+
+---
+class: center, middle
+
+When true, the :start_permanent option starts your application in permanent mode, which means the Erlang VM will crash if your application's supervision tree shuts down.
+
+---
+class: center, middle
+
+```bash
+MIX_ENV=prod mix compile
+```
+
+---
+class: center, middle
+
 Code
 https://github.com/AgarwalConsulting/elixir_training