Readme update

Author: neumond

README.md

@@ -1,8 +1,50 @@
 # Pythonized ComputerCraft API
 
-```
+First, you need to start a server:
+
+```bash
+cd your_folder_with_programs
 python -m computercraft.server
 ```
 
+Current directory is the place for your amazing programs.
+Server tracks files inside this directory and reloads if necessary.
+You don't (always) have to restart server if you change your programs.
+
+Create simple program named `hello.py`:
+
+```python
+async def program(api):
+    await api.print('Hello world!')
+```
+
+In minecraft, open up any computer and type:
+
+```bash
+wget http://127.0.0.1:8080/ py
+py hello
+```
+
+`py` is short Lua program that interacts with the server.
+Argument is the name of program without `.py`.
+In everything else it works exactly like native program on Lua.
+`api` object contains almost everything *as is* in ComputerCraft documentation:
+
+```python
+async def program(api):
+    await api.disk.eject('right')
+    await api.print(await api.os.getComputerLabel())
+    # ...
+```
+
+Using python coroutines allows launching commands in parallel, effectively replacing `parallel` API:
+
+```python
+async def program(api):
+    # Since os.sleep is mostly waiting for events, it doesn't block execution of parallel threads
+    # and this snippet takes approximately 2 seconds to complete.
+    await asyncio.gather(api.os.sleep(2), api.os.sleep(2))
+```
+
 TODO:
 - use current dir for programs