Prevent a crash serializing configs.

zebrad/src/commands/config.rs

@@ -28,7 +28,10 @@ impl Runnable for ConfigCmd {
 
 "
         .to_owned(); // The default name and location of the config file is defined in ../commands.rs
-        output += &toml::to_string_pretty(&default_config)
+        // this avoids a ValueAfterTable error
+        // https://github.com/alexcrichton/toml-rs/issues/145
+        let conf = toml::Value::try_from(default_config).unwrap();
+        output += &toml::to_string_pretty(&conf)
             .expect("default config should be serializable");
         match self.output_file {
             Some(ref output_file) => {