Twitter tweet classification
You should be reading about text classification with supervised learning technique. You could chose a neural network such as CNN implementation and use it to your data. But you have to first prepare your data by cleaning it up and labelling it with respect to your desired category. For example,


You should collect the tweet data and label each tweet or set of words as job or news with respect to their original category.
Then you should use the prepared data and labels to train the chosen network.
Read about k fold cross validation and segregate data in such a way so that systematic iterative training and validation can be done and tweaks to the network could be made.
Finally once the training is completed you could use the model to test it on unseen test data.


These are common steps involved in text classification. It should be customized according to your need.  You could google profanity filter which is mostly developed with a NLP type classifier. That would help you a lot.