Add 'red light, green light' tutorial (#436)

docs/tutorials.md

@@ -60,5 +60,11 @@ Step by step guides to coding your @boardname@.
   "cardType": "tutorial",
   "url":"/tutorials/line-following",
   "imageUrl":"/static/tutorials/line-following.png"
+}, {
+  "name": "Red Light, Green Light",
+  "description": "Play Red Light, Green Light using the Color sensor and the robot.",
+  "cardType": "tutorial",
+  "url":"/tutorials/redlight-greenlight",
+  "imageUrl":"/static/tutorials/redlight-greenlight.png"
 }]
 ```

docs/tutorials/redlight-greenlight.md

@@ -0,0 +1,62 @@
+# Red Light, Green Light
+
+## Introduction @fullscreen
+
+Use the ``||sensors:pause color sensor||`` block to play Red Light, Green Light with your @boardname@ robot! 
+
+![Brick simulation with color sensor and motors](/static/tutorials/redlight-greenlight/redlight-greenlight.gif)
+
+## Step 1
+
+Open the ``||sensors:Sensors||`` Toolbox drawer. Drag out **2** ``||sensors:pause color sensor||`` blocks onto the Workspace, and drop them into the ``||loops:forever||`` loop.
+
+```blocks
+forever(function () { 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Blue) 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Blue) 
+}) 
+```
+
+## Step 2
+
+In the first ``||sensors:pause color sensor||`` block, use the second drop-down menu to select the "Green" color.  In the second ``||sensors:pause color sensor||`` block, use the second drop-down menu to select the "Red" color. 
+
+![Color selection dropdown](/static/tutorials/redlight-greenlight/pause-color-sensor-dropdown.png)
+
+```blocks
+forever(function () { 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Green) 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Red) 
+}) 
+```
+
+## Step 3
+
+Open the ``||motors:Motors||`` Toolbox drawer. Drag out a ``||motors:tank large motors||`` block onto the Workspace, and drop in between the ``||sensors:pause color sensor||`` blocks.
+
+```blocks
+forever(function () { 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Green) 
+    motors.largeBC.tank(50, 50) 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Red) 
+}) 
+```
+
+## Step 4
+
+Open the ``||motors:Motors||`` Toolbox drawer. Drag out a ``||motors:stop all motors||`` block onto the Workspace, and drop it in after the second ``||sensors:pause color sensor||`` block in the ``||loops:forever||`` loop.
+
+```blocks
+forever(function () { 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Green) 
+    motors.largeBC.tank(50, 50) 
+    sensors.color3.pauseUntilColorDetected(ColorSensorColor.Red) 
+    motors.stopAll() 
+})
+```
+
+## Step 5
+ 
+Now, plug your @boardname@ into the computer with the USB cable, and click the **Download** button at the bottom of your screen. Follow the directions to save your program to the brick.
+
+Attach a Color Sensor to Port 3 of your brick, and attach your brick to a driving base with large motors attached to Ports B and C. See the building instructions for: _Driving Base with Color Sensor Forward_. Test your program by putting a green or red piece of paper or LEGO brick in front of the color sensor.