Added global gitignore file.

See https://stackoverflow.com/questions/7335420/global-git-ignore
Using default location.

private_dot_config/git/ignore

@@ -0,0 +1,42 @@
+# From https://gist.github.com/octocat/9257657
+# Compiled source #
+###################
+*.com
+*.class
+*.dll
+*.exe
+*.o
+*.so
+
+# Packages #
+############
+# it's better to unpack these files and commit the raw source
+# git has its own built in compression methods
+*.7z
+*.dmg
+*.gz
+*.iso
+*.jar
+*.rar
+*.tar
+*.zip
+
+# Logs and databases #
+######################
+*.log
+*.sql
+*.sqlite
+
+# OS generated files #
+######################
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# User settings for SG
+# ####################
+log4j2-test-sg.xml