begin documenting usage and and upgarde of dependencies, also comment…

…ing source code in compile

docs/usage/index.rst

@@ -0,0 +1,59 @@
+Usage of RestrictedPython
+=========================
+
+Basics
+------
+
+RestrictedPython do have tree major scopes:
+
+* compile_restricted methods
+
+  * compile_restricted
+  * compile_restricted_exec
+  * compile_restricted_eval
+  * compile_restricted_single
+  * compile_restricted_function
+
+* restricted builtins
+
+  * safe_builtins
+  * limited_builtins
+  * utility_builtins
+
+* Helper Moduls
+
+  * PrintCollector
+
+heading
+-------
+
+The general workflow to execute Python code that is loaded within a Python program is:
+
+.. code:: Python
+
+    source_code = """
+    def do_something():
+        pass
+    """
+
+    byte_code = compile(source_code, filename='<inline code>', mode='exec')
+    exec(byte_code)
+    do_something()
+
+With RestrictedPython that workflow should be as straight forward as possible:
+
+.. code:: Python
+
+    from RestrictedPython import compile_restricted as compile
+
+    source_code = """
+    def do_something():
+        pass
+    """
+
+    byte_code = compile(source_code, filename='<inline code>', mode='exec')
+    exec(byte_code)
+    do_something()
+
+With that simple addition ``from RestrictedPython import compile_restricted as compile`` it uses a predefined policy that checks and modify the source code and checks against restricted subset of the Python language.
+Execution of the compiled source code is still against the full avaliable set of library modules and methods.