feat: pg_isready in postgres import

Fixed issue where arguments passed to `compose stop` weren't passed to
the underlying command. Added pg_isready call between each command call
in restore script.

src/command_builder.rs

@@ -4,8 +4,9 @@ use std::{
     ffi::OsStr,
     fmt::Display,
     fs::{File, OpenOptions},
+    os::unix::process::CommandExt,
     path::PathBuf,
-    process::{Command, Stdio},
+    process::{Child, Command, Stdio},
 };
 
 use crate::debug_println;
@@ -81,6 +82,10 @@ impl CommandBuilder {
         Ok(())
     }
 
+    pub fn spawn(mut self) -> Result<(Child)> {
+        Ok(self.build()?.spawn()?)
+    }
+
     pub fn exec_redirect_stdout(mut self, stdio: Stdio) -> Result<()> {
         self.build()?.stdout(stdio).spawn()?.wait()?;
         Ok(())