Re-add serde_derive

Cargo.lock

@@ -334,6 +334,7 @@ dependencies = [
  "rpassword 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rust-crypto 0.2.36 (git+https://github.com/awmath/rust-crypto.git?branch=avx2)",
  "serde 0.9.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 0.9.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 0.9.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-core 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",

Cargo.toml

@@ -43,6 +43,7 @@ rand = "0.3.13"
 rpassword = "0.3.0"
 rust-crypto = { git = "https://github.com/awmath/rust-crypto.git", branch = "avx2" }
 serde = "0.9.6"
+serde_derive = "0.9.6"
 serde_json = "0.9.5"
 tokio-core = "0.1.2"
 tokio-io = "0.1"