add information about content client provider to readme

features/common/README.md

@@ -0,0 +1,26 @@
+# Common
+
+In that readme will be stored several notes about working with common parts in all your modules
+
+## ModuleLoader
+
+This module has been created to allow your plugins to load dynamically after build of the server and client
+
+### Server
+
+To declare your module loader you should create **_class_** realization of `ServerModuleLoader` and put the classname of that
+realization into the `modules` section as a string.
+
+### Client
+
+On the client side you also should create your own realization of `ModuleLoader`, but instead of some config you will
+need to create some `private val` property on the top level in your `ModuleLoader` realization file. Example:
+
+```kotlin
+
+object SomeModuleLoader : ModuleLoader {
+    // body
+}
+
+private val someModuleLoaderProperty = AdditionalModules.addModule(SomeModuleLoader) // that is important part
+```