Group Thoughtful: Close issue#7

[JiayangLJY]

• A config file was used to allow flexible maching learing model selection.
• The order of features (form data) was also maintained in the config file to loosen the couple between model training and predicting.
• Data type conversion was now conducted in the data model itself to improve conhesion.
• Test code ensured each step, including model training, data processing and input validation were correct.