PAN-6 Fixed the user creation for .travis.yml

.travis.yml

@@ -4,6 +4,14 @@ services:
 
 install: true
 
+addons:
+  apt:
+    sources:
+      - mysql-5.7-trusty
+    packages:
+      - mysql-server
+      - mysql-client
+
 before_install:
   - chmod +x pandamonium-theorem-prover/gradlew
   - cd pandamonium-theorem-prover