Fix code duplication

[gabrielademoraes]

Description

Fix code duplication detected by code climate on the back end repository. (https://codeclimate.com/github/fga-gpp-mds/Falko-2017.2-BackEnd/issues?category=duplication&engine_name%5B%5D=structure&engine_name%5B%5D=duplication)

Expected behavior

Don't have any duplication.

Current behavior

Has code duplication.

Checklist

• This issue has a significant name.
• This issue has labels.
• This issue has screenshots (if necessary).