[MXNET-1333] Estimator and Fit API

ci/docker/runtime_functions.sh

@@ -1350,6 +1350,16 @@ nightly_scala_demo_test_cpu() {
     bash bin/run_im.sh
 }
 
+nightly_estimator() {
+    set -ex
+    cd /work/mxnet/tests/nightly/estimator
+    export PYTHONPATH=/work/mxnet/python/
+    python test_estimator_cnn.py --type gpu
+    python test_sentiment_rnn.py --type gpu
+    python test_estimator_cnn.py --type cpu
+    python test_sentiment_rnn.py --type cpu
+}
+
 # Deploy
 
 deploy_docs() {

python/mxnet/gluon/contrib/estimator/__init__.py

@@ -0,0 +1,21 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# pylint: disable=wildcard-import
+"""Gluon Estimator Module"""
+from .estimator import *
+from .event_handler import *