update readme

Author: dropwhile

README.md

@@ -8,9 +8,19 @@ gleam add gbase32_clockwork
 ```
 ```gleam
 import gbase32_clockwork
+import gbase32_clockwork/options.{Lowercase}
 
 pub fn main() {
-  // TODO: An example of the project in use
+  let codebook = gbase32_clockwork.new([])
+
+  codebook.encode("foobar")
+  |> should.equal(Ok("CSQPYRK1E8"))
+
+  // to emit as lowercase
+  let codebook_lc = gbase32_clockwork.new([Lowercase])
+  
+  codebook.encode("foobar")
+  |> should.equal(Ok("csqpyrk1e8"))
 }
 ```