moving the docs to github

docs_raw/docs/contributing/add_env.md

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+Adding a new environment to Coach is as easy as solving CartPole. 
+
+There are a few simple steps to follow, and we will walk through them one by one.
+
+1.  Coach defines a simple API for implementing a new environment which is defined in environment/environment_wrapper.py.
+    There are several functions to implement, but only some of them are mandatory. 
+
+    Here are the important ones:
+
+            def _take_action(self, action_idx):
+                """
+                An environment dependent function that sends an action to the simulator.
+                :param action_idx: the action to perform on the environment.
+                :return: None
+                """
+                pass
+
+            def _preprocess_observation(self, observation):
+                """
+                Do initial observation preprocessing such as cropping, rgb2gray, rescale etc.
+                Implementing this function is optional.
+                :param observation: a raw observation from the environment
+                :return: the preprocessed observation
+                """
+                return observation
+
+            def _update_state(self):
+                """
+                Updates the state from the environment.
+                Should update self.observation, self.reward, self.done, self.measurements and self.info
+                :return: None
+                """
+                pass
+
+            def _restart_environment_episode(self, force_environment_reset=False):
+                """
+                :param force_environment_reset: Force the environment to reset even if the episode is not done yet.
+                :return:
+                """
+                pass
+
+            def get_rendered_image(self):
+                """
+                Return a numpy array containing the image that will be rendered to the screen.
+                This can be different from the observation. For example, mujoco's observation is a measurements vector.
+                :return: numpy array containing the image that will be rendered to the screen
+                """
+                return self.observation
+
+
+2.  Make sure to import the environment in environments/\_\_init\_\_.py:
+        
+        from doom_environment_wrapper import *
+        
+    Also, a new entry should be added to the EnvTypes enum mapping the environment name to the wrapper's class name:
+        
+        Doom = "DoomEnvironmentWrapper"
+    
+                
+3. In addition a new configuration class should be implemented for defining the environment's parameters and placed in configurations.py. 
+For instance, the following is used for Doom:
+
+        class Doom(EnvironmentParameters):
+            type = 'Doom'
+            frame_skip = 4
+            observation_stack_size = 3
+            desired_observation_height = 60
+            desired_observation_width = 76
+            
+4. And that's it, you're done. Now just add a new preset with your newly created environment, and start training an agent on top of it.