Merge pull request #195 from hongchaodeng/patch-1

README.md: fix example

Author: Zhou Hao

README.md

@@ -28,7 +28,7 @@ The following examples assume you have a [image-layout](https://github.com/openc
 One way to acquire that image is with [skopeo](https://github.com/projectatomic/skopeo#installing):
 
 ```
-$ skopeo copy docker://busybox oci:busybox-oci
+$ skopeo copy docker://busybox oci:busybox-oci:latest
 ```
 
 ### oci-image-tool-create

man/oci-image-tool-create.1.md

@@ -33,7 +33,7 @@ runtime-spec-compatible `dest/config.json`.
 
 # EXAMPLES
 ```
-$ skopeo copy docker://busybox oci:busybox-oci
+$ skopeo copy docker://busybox oci:busybox-oci:latest
 $ mkdir busybox-bundle
 $ oci-image-tool create --ref latest busybox-oci busybox-bundle
 $ cd busybox-bundle && sudo runc run busybox

man/oci-image-tool-unpack.1.md

@@ -27,7 +27,7 @@ oci-image-tool unpack \- Unpack an image or image source layout
 
 # EXAMPLES
 ```
-$ skopeo copy docker://busybox oci:busybox-oci
+$ skopeo copy docker://busybox oci:busybox-oci:latest
 $ mkdir busybox-bundle
 $ oci-image-tool unpack --ref latest busybox-oci busybox-bundle
 $ tree busybox-bundle

man/oci-image-tool-validate.1.md

@@ -26,7 +26,7 @@ oci-image-tool validate \- Validate one or more image files
 
 # EXAMPLES
 ```
-$ skopeo copy docker://busybox oci:busybox-oci
+$ skopeo copy docker://busybox oci:busybox-oci:latest
 $ oci-image-tool validate --type imageLayout --ref latest busybox-oci
 busybox-oci: OK
 ```