Update cheatsheets

mix

@@ -0,0 +1,29 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# mix
+
+> Build tool that provides tasks for creating, compiling, and testing Elixir projects, managing its dependencies, and more.
+> More information: <https://hexdocs.pm/mix>.
+
+- Execute a particular file:
+
+`mix run {{my_script.exs}}`
+
+- Create a new project:
+
+`mix new {{project_name}}`
+
+- Compile project:
+
+`mix compile`
+
+- Run project tests:
+
+`mix test`
+
+- Display help:
+
+`mix help`