REFACTOR Go doc now support markdown file!

omg at last.

core/README.md

@@ -0,0 +1,17 @@
+Package core allows to use pgrebase as a library in your own code.
+
+To use it, your first need to initialize it:
+
+    err := core.Init(databaseUrl, sqlDir)
+
+`databaseUrl` is the postgres connection string as used by
+`database/sql.Open`, `sqlDir` is the path to your sql sources, and watch is
+a flag you can set to true to keep watching sqlDir for changes.
+
+Once pgrebase is initialized, call `Process()` to load your source files
+into database.
+
+If you want to keep watching FS for changes after than, you can call
+`Watch()`. Note that this function won't return, so unless that's what you
+want, you should run it in a goroutine.
+