Add new tool to repository for initializing the first challenge file.

src/bin/new.rs

@@ -0,0 +1,24 @@
+extern crate powersoftau;
+use powersoftau::*;
+
+use std::fs::OpenOptions;
+use std::io::{Write, BufWriter};
+
+fn main() {
+    let writer = OpenOptions::new()
+                            .read(false)
+                            .write(true)
+                            .create_new(true)
+                            .open("challenge").expect("unable to create `./challenge`");
+
+    let mut writer = BufWriter::new(writer);
+
+    // Write a blank BLAKE2b hash:
+    writer.write_all(&blank_hash().as_slice()).expect("unable to write blank hash to `./challenge`");
+
+    let acc = Accumulator::new();
+    acc.serialize(&mut writer, UseCompression::No).expect("unable to write fresh accumulator to `./challenge`");
+    writer.flush().expect("unable to flush accumulator to disk");
+
+    println!("Wrote a fresh accumulator to `./challenge`");
+}