docs: add readme with usage

Author: justinawrey

README.md

@@ -1 +1,39 @@
-# bash
+# bash :boxing_glove:
+
+Ergonomically run `bash` commands in Deno.
+
+## Usage
+
+Run any `bash` command:
+
+```ts
+import { bash } from "https://deno.land/x/bash/mod.ts";
+
+const result = await bash("echo 'hello world'");
+console.log(result); // hello world
+```
+
+If the underlying command fails, `bash` will throw an error:
+
+```ts
+import { bash, BashError } from "https://deno.land/x/bash/mod.ts";
+
+try {
+  const result = await bash("laskdjf");
+} catch (error) {
+  if (error instanceof BashError) {
+    console.error(error.message);
+  }
+}
+```
+
+By default, `bash` will strip the trailing newline from both the `stdout` output
+and `stderr` output. If you want to disable this behavior, pass
+`{ stripTrailingNewline: true }` as the second argument:
+
+```ts
+import { bash } from "https://deno.land/x/bash/mod.ts";
+
+const result = await bash("echo 'hello world'", { stripTrailingNewline: true });
+console.log(result); // hello world\n
+```