Correct typo in README, do basic form URL validation to make sure it is an image, the only thing Pinry currently supports.

README.md

@@ -28,7 +28,7 @@ for bad code, I'll simply work with you to improve it.
 
 Have virtualenv and pip installed. You may also need to have the build
 dependencies for PIL installed. (If you are on Ubuntu you can do this by typing
-"sudo build-dep python-imaging".)
+"sudo apt-get build-dep python-imaging".)
 
     $ git clone git://github.com/overshard/pinry.git
     $ cd pinry

pinry/pins/forms.py

@@ -6,6 +6,14 @@ from .models import Pin
 class PinForm(forms.ModelForm):
     url = forms.CharField(label='URL')
 
+    def clean_url(self):
+        data = self.cleaned_data['url']
+        image_file_types = ['png', 'gif', 'jpeg', 'jpg']
+        file_type = data.split('.')[-1]
+        if file_type.lower() not in image_file_types:
+            raise forms.ValidationError("Requested URL is not an image file. Only images are currently supported.")
+        return data
+
     class Meta:
         model = Pin
         exclude = ['image']