Add brief instructions to readme

Author: cameronfyfe

README.md

@@ -1,2 +1,20 @@
 # podcast-api-rust
 Rust library for the Listen Notes Podcast API
+
+## Check
+ - formatting: `cargo fmt --check`  
+ - valid code: `cargo check`  
+ - linting: `cargo clippy`  
+
+## Build
+`cargo build`  
+
+## Test
+`cargo test`
+
+## Usage
+Add this to your `Cargo.toml`:
+```toml
+[dependencies]
+podcast-api = "0.1"
+```