Implement CSV import and conversion to contestants

spec/factories/csv_imports.rb

@@ -3,6 +3,7 @@
 # Table name: csv_imports
 #
 #  id         :integer          not null, primary key
+#  content    :string           not null
 #  separator  :string           not null
 #  created_at :datetime         not null
 #  updated_at :datetime         not null

spec/models/csv_import_spec.rb

@@ -3,6 +3,7 @@
 # Table name: csv_imports
 #
 #  id         :integer          not null, primary key
+#  content    :string           not null
 #  separator  :string           not null
 #  created_at :datetime         not null
 #  updated_at :datetime         not null