Merge branch '29-add-graphql-type-for-paymant-choices' into 'master'

Resolve "Add graphql type for paymant choices"

Closes #29

See merge request !74

aleksis/apps/tezor/schema/client.py

+import graphene
+
+
+class PaymentVariantChoiceType(graphene.ObjectType):
+    variant = graphene.String()
+    text = graphene.String()
+
+    def resolve_variant(root, info, **kwargs):
+        return root[0]
+
+    def resolve_text(root, info, **kwargs):
+        return root[1]