Point travis badges to master branch.
Point travis badges to master branch.

mitre-cyber-academy/registration-app,mitre-cyber-academy/ctf-scoreboard,mitre-cyber-academy/ctf-scoreboard,mitre-cyber-academy/registration-app,mitre-cyber-academy/registration-app,mitre-cyber-academy/ctf-scoreboard,mitre-cyber-academy/ctf-scoreboard