Switch to using CustomError because a boxed StdError is not Send.

src/main.rs

@@ -6,12 +6,14 @@ use self::cli::parameters::Cli;
 use self::cli::parameters::Commands;
 use self::command::build::build_site;
 use self::command::init::init_writer_folder;
+use self::error::CustomError;
 mod blog_post;
 mod cli;
 mod command;
 mod config;
+mod error;
 
-fn main() -> Result<ExitCode, Box<dyn std::error::Error>> {
+fn main() -> Result<ExitCode, CustomError> {
     let rt = tokio::runtime::Runtime::new()?;
     rt.block_on(async {
         let main_body_result = main_body().await;
@@ -19,7 +21,7 @@ fn main() -> Result<ExitCode, Box<dyn std::error::Error>> {
     })
 }
 
-async fn main_body() -> Result<ExitCode, Box<dyn std::error::Error>> {
+async fn main_body() -> Result<ExitCode, CustomError> {
     let args = Cli::parse();
     match args.command {
         Commands::Init(args) => {