Docker login (#894)

* Add docker_login rule

* Add docker_login rule

* Whitespace fix

* Fix typo in test case

* Fix typo in test case

* Add test cases

tests/rules/test_docker_login.py

@@ -0,0 +1,37 @@
+from thefuck.rules.docker_login import match, get_new_command
+from thefuck.types import Command
+
+
+def test_match():
+    err_response1 = """
+    Sending build context to Docker daemon  118.8kB
+Step 1/6 : FROM foo/bar:fdb7c6d
+pull access denied for foo/bar, repository does not exist or may require 'docker login'
+"""
+    assert match(Command('docker build -t artifactory:9090/foo/bar:fdb7c6d .', err_response1))
+
+    err_response2 = """
+    The push refers to repository [artifactory:9090/foo/bar]
+push access denied for foo/bar, repository does not exist or may require 'docker login'
+"""
+    assert match(Command('docker push artifactory:9090/foo/bar:fdb7c6d', err_response2))
+
+    err_response3 = """
+    docker push artifactory:9090/foo/bar:fdb7c6d
+The push refers to repository [artifactory:9090/foo/bar]
+9c29c7ad209d: Preparing
+71f3ad53dfe0: Preparing
+f58ee068224c: Preparing
+aeddc924d0f7: Preparing
+c2040e5d6363: Preparing
+4d42df4f350f: Preparing
+35723dab26f9: Preparing
+71f3ad53dfe0: Pushed
+cb95fa0faeb1: Layer already exists
+"""
+    assert not match(Command('docker push artifactory:9090/foo/bar:fdb7c6d', err_response3))
+
+
+def test_get_new_command():
+    assert get_new_command(Command('docker build -t artifactory:9090/foo/bar:fdb7c6d .', '')) == 'docker login && docker build -t artifactory:9090/foo/bar:fdb7c6d .'
+    assert get_new_command(Command('docker push artifactory:9090/foo/bar:fdb7c6d', '')) == 'docker login && docker push artifactory:9090/foo/bar:fdb7c6d'