fix link (#500)

README.md

@@ -30,7 +30,7 @@ When libraries are installed from Git repositories, the repository is expected
 to have version tags following a [semver](http://semver.org/)-like format,
 prefixed with a `v`. Examples: `v1.2.3`, `v2.0.0-rc1` or `v2017.04.1`.
 
-Please see the [SPEC](https://github.com/ysbaddaden/shards/blob/master/SPEC.md)
+Please see the [SPEC](https://github.com/crystal-lang/shards/blob/master/docs/shard.yml.adoc)
 for more details about the `shard.yml` format.
 
 
@@ -44,7 +44,7 @@ then run `make release=1`and copy `bin/shards` into your `PATH`. For
 example `/usr/local/bin`.
 
 You are now ready to create a `shard.yml` for your projects (see details in
-[SPEC](https://github.com/ysbaddaden/shards/blob/master/SPEC.md)). You can type
+[SPEC](https://github.com/crystal-lang/shards/blob/master/docs/shard.yml.adoc)). You can type
 `shards init` to have an example `shard.yml` file created for your project.
 
 Run `shards install` to install your dependencies, which will lock your