Added image content type validation to only allowing jpg images.

app/models/budget/investment.rb

@@ -17,6 +17,8 @@ class Budget
     acts_as_paranoid column: :hidden_at
     include ActsAsParanoidAliases
 
+    has_attached_file :image, styles: { large: "600x600>", medium: "300x300>", thumb: "100x100>" }
+
     belongs_to :author, -> { with_hidden }, class_name: 'User', foreign_key: 'author_id'
     belongs_to :heading
     belongs_to :group
@@ -28,9 +30,6 @@ class Budget
     has_many :comments, as: :commentable
     has_many :milestones
 
-    has_attached_file :image, styles: { large: "600x600>"  ,medium: "300x300>", thumb: "100x100>" }
-    validates_attachment_content_type :image, content_type: /\Aimage\/.*\z/
-
     validates :title, presence: true
     validates :author, presence: true
     validates :description, presence: true
@@ -41,6 +40,7 @@ class Budget
     validates :title, length: { in: 4..Budget::Investment.title_max_length }
     validates :description, length: { maximum: Budget::Investment.description_max_length }
     validates :terms_of_service, acceptance: { allow_nil: false }, on: :create
+    validates_attachment :image, content_type: { content_type: ["image/jpeg"] }
 
     scope :sort_by_confidence_score, -> { reorder(confidence_score: :desc, id: :desc) }
     scope :sort_by_ballots,          -> { reorder(ballot_lines_count: :desc, id: :desc) }

spec/models/budget/investment_spec.rb

@@ -29,6 +29,30 @@ describe Budget::Investment do
     end
   end
 
+  describe "#image" do
+
+    describe "extesion" do
+      it "should not be valid with '.png' extension" do
+        investment.image = File.new("spec/fixtures/files/logo_header.png")
+
+        expect(investment).to_not be_valid
+      end
+
+      it "should not be valid with '.gif' extension" do
+        investment.image = File.new("spec/fixtures/files/logo_header.gif")
+
+        expect(investment).to_not be_valid
+      end
+
+      it "should be valid with '.jpg' extension" do
+        investment.image = File.new("spec/fixtures/files/logo_header.jpg")
+
+        expect(investment).to be_valid
+      end
+    end
+
+  end
+
   it "sanitizes description" do
     investment.description = "<script>alert('danger');</script>"
     investment.valid?