Issues Democratic hopefuls are talking about on social media

For the Washington Post, Kevin Schaul and Kevin Uhrmacher parsed the social media of Democrats:

A Washington Post analysis of more than 5,600 social media posts from March found significant differences in the issues that each candidate emphasized. While most candidates discussed social justice and health care, only a few talked much about foreign policy or immigration. No candidate made gun control a first or second priority in their social media strategy during the month.

I hope the Post explores how the issues change over time.