feat: mirror can set to none, set to rust when confit is none

README.md

@@ -3,6 +3,14 @@
 Docker build tool, build software using docker
 
 
+Install:
+
+```shell
+$ cargo install dockerbuild
+--OR--
+$ cargo install --git https://git.hatter.ink/hatter/dockerbuild.git
+```
+
 Config file:
 * `~/.dockerbuild.json`
 * `/etc/dockerbuild.json`
@@ -31,3 +39,4 @@ $ dockerbuild :rustc --version
 Docker official images:
 https://hub.docker.com/_/rust
 
+