Added validation for countries, added patch method for profile page, code improvements and small fixes

solution/pulse/users/validators.py

@@ -0,0 +1,16 @@
+from countries.models import Country
+from django.core.exceptions import ValidationError
+from django.core.validators import BaseValidator
+from django.utils.deconstruct import deconstructible
+
+
+@deconstructible
+class CountryCodeValidator(BaseValidator):
+    def __init__(self, message=None):
+        self.message = message or "There is no such country"
+
+    def __call__(self, value):
+        try:
+            Country.objects.get(alpha2=value)
+        except Country.DoesNotExist:
+            raise ValidationError(self.message) from None