Final changes 2 (#183)

* Import, Export fixes

IMPORTAR STACKEHOKDERS; COORDINADORES; SUPERVISORES

IGNORAR REPETIDOS AL MOMENTO DE IMPORTAR DE EXCEL

EXPORTACIONES DE TUTORES; STUDENTS;

* 1 line fix

app/models/tutor.rb

@@ -12,6 +12,9 @@ def self.import(file)
 
 		xlsx = Roo::Spreadsheet.open(file.path)
     xlsx.drop(1).each do |row|
+
+      username = row[0]
+
       if !all_tutors.include?(username)
         str = (0...6).map { o[rand(o.length)] }.join
         Tutor.create(