Merge pull request coderoad#290 from coderoad/tutorial-select-yaml

load tutorials from yaml

Author: ShMcK

web-app/.env.example

@@ -3,4 +3,4 @@ VERSION=0.1.0
 NODE_ENV=local
 REACT_APP_DEBUG=false
 REACT_APP_LOG=false
-REACT_APP_TUTORIAL_LIST_URL=https://raw.githubusercontent.com/coderoad/tutorials/master/tutorials.json
+REACT_APP_TUTORIAL_LIST_URL=https://raw.githubusercontent.com/coderoad/tutorials/master/tutorials.yml