Update ftml for Keras changes to optimizers (#137)

* Update ftml for Keras changes to optimizers

* fix import

keras_contrib/optimizers/ftml.py

@@ -2,6 +2,7 @@ from __future__ import absolute_import
 from keras.optimizers import Optimizer
 from .. import backend as K
 from keras.utils.generic_utils import get_custom_objects
+from keras.legacy import interfaces
 
 
 class FTML(Optimizer):
@@ -30,7 +31,8 @@ class FTML(Optimizer):
         self.epsilon = epsilon
         self.inital_decay = decay
 
-    def get_updates(self, params, constraints, loss):
+    @interfaces.legacy_get_updates_support
+    def get_updates(self, loss, params):
         grads = self.get_gradients(loss, params)
         self.updates = [K.update_add(self.iterations, 1)]
 
@@ -61,10 +63,11 @@ class FTML(Optimizer):
             self.updates.append(K.update(d, d_t))
 
             new_p = p_t
-            # apply constraints
-            if p in constraints:
-                c = constraints[p]
-                new_p = c(new_p)
+
+            # Apply constraints.
+            if getattr(p, 'constraint', None) is not None:
+                new_p = p.constraint(new_p)
+
             self.updates.append(K.update(p, new_p))
         return self.updates