Update README.md

Author: jesprider

README.md

@@ -1,2 +1,35 @@
-sourcejs-spec-dependencies
-==========================
+# Spec Dependencies (crosslinks)
+
+Spec Dependencies is [SourceJS](http://sourcejs.com) plugin for adding crosslinks section into each spec. It predicts used specs through the css selectors used in current spec.
+
+![image](http://monosnap.com/image/gG9KatayyGGg5BxYt3704OIIQHUg0V.png)
+
+Compatible with SourceJS v0.4+.
+
+## How to use
+
+Spec Dependencies automatically predicts all specs, that used in current spec ("most likely it uses" section on the picture above). If you also want to see next section to check which specs use current ("this spec used by"), you have to update info.json of the specs with "usedSpecs" property. Value of "usedSpecs" should be an array even for only element.
+
+```
+// info.json of Example spec (/url/to/example/spec)
+{
+  "author": ...,
+  "title": ...,
+  ...,
+  "usedSpecs": ["/url/to/used/spec", "/url/to/used/spec1", ...]
+}
+```
+
+Next, SourceJS core builds inverted dependencies tree and save it to `data/spec_dependencies_tree.json`:
+```
+{
+    "/url/to/used/spec": [
+        "/url/to/example/spec"
+    ],
+    "/url/to/used/spec1": [
+       "/url/to/example/spec"
+    ]
+}
+```
+
+After that plugin uses this tree to build the "this spec used by" section.