adding mysql 5.6

.travis.yml

@@ -16,4 +16,18 @@ services:
 
 addons:
   hosts:
-    - 127.0.0.1 dockerhost
+    - 127.0.0.1 dockerhost
+
+install:
+  - "sudo apt-get remove mysql-common mysql-server-5.5 mysql-server-core-5.5 mysql-client-5.5 mysql-client-core-5.5"
+  - "sudo apt-get autoremove"
+  - "sudo apt-get install libaio1"
+  - "wget -O mysql-5.6.25.deb http://dev.mysql.com/get/Downloads/MySQL-5.6/mysql-5.6.25-debian6.0-x86_64.deb/from/http://cdn.mysql.com/"
+  - "sudo dpkg -i mysql-5.6.25.deb"
+  - "sudo cp /opt/mysql/server-5.6/support-files/mysql.server /etc/init.d/mysql.server"
+  - "sudo ln -s /opt/mysql/server-5.6/bin/* /usr/bin/"
+  # some config values were changed since 5.5
+  - "sudo sed -i'' 's/table_cache/table_open_cache/' /etc/mysql/my.cnf"
+  - "sudo sed -i'' 's/log_slow_queries/slow_query_log/' /etc/mysql/my.cnf"
+  - "sudo sed -i'' 's/basedir[^=]\\+=.*$/basedir = \\/opt\\/mysql\\/server-5.6/' /etc/mysql/my.cnf"
+  - "sudo /etc/init.d/mysql.server start"