Update rails to avoid security problems

[fedegratti]

I suggest updating rails (4.2.5) to rails (4.2.5.2) to prevent security problems.

[fedegratti]

Hey there, I was doing a security scan to this repo and I saw you have several security issues related to rails.
Looking for a solution I realized that updating rails to the following version would be solved the problems listed below:

Security issues on rails (4.2.5):
CVE-2016-2098
CVE-2016-0752
CVE-2016-0751
CVE-2015-7577
CVE-2015-7581
CVE-2016-0753

I hope it helps!