Adds dockerignore to the repo

Addition of .dockerignore considerably reduces the size
of newly created containers, as well as time needed for
building them.

Signed-off-by: Jiri Podivin <jpodivin@redhat.com>
Change-Id: Ifa94774862c2364483454a648377b0f333b72b99

.dockerignore

@@ -0,0 +1,66 @@
+# Docker image doesn't need any files that git doesn't track.
+#Therefore the .dockerignore largely follows the structure of .gitignore.
+*.py[cod]
+
+# C extensions
+*.so
+
+# Packages
+*.egg*
+*.egg-info
+dist
+build
+eggs
+parts
+bin
+var
+sdist
+develop-eggs
+.installed.cfg
+lib
+lib64
+
+# Installer logs
+pip-log.txt
+
+# Unit test / coverage reports
+cover/
+.coverage*
+!.coveragerc
+.tox
+nosetests.xml
+.testrepository
+.venv
+.stestr/*
+
+# Translations
+*.mo
+
+# Mr Developer
+.mr.developer.cfg
+.project
+.pydevproject
+
+# Complexity
+output/*.html
+output/*/index.html
+
+# Sphinx
+doc/build
+doc/source/reference/api/
+
+# pbr generates these
+AUTHORS
+ChangeLog
+
+# Editors
+*~
+.*.swp
+.*sw?
+
+# Files created by releasenotes build
+releasenotes/build
+
+# Ansible specific
+hosts
+*.retry