Build docker image from local source.

Currently we check out the code from gerrit to build the image, but this
makes it hard to specify a particular commit to build and impossible to
build a docker image from code that isn't yet checked in to git. This patch
will build the image from the local ONOS source.

Change-Id: I5936cb02d553aed3d9b6b5a260483759e36049c5
diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..12481bb
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,30 @@
+*~
+*.class
+.classpath
+.project
+.pydevproject
+.settings
+.javacp*
+.checkstyle
+target
+*.iml
+*.pyc
+dependency-reduced-pom.xml
+.idea
+*.DS_Store
+.buckd
+buck-out
+.buckconfig.local
+.buckjavaargs*
+bucklets/plugins/
+.watchmanconfig
+.git
+
+/bin/
+
+web/gui/src/main/webapp/tests/node_modules
+web/gui/src/test/_karma/node_modules
+web/gui/src/main/webapp/node_modules/
+
+npm-debug.log
+sonar-project.properties