Added instructions about general IDE's in gitignore

.gitignore file was missing a very general and easy
to forget instruction about general IDE's
contributors(new) use for developing code.

This instruction would be clear idea to add there
respective IDE's generated files to local git
configuration file so that they could be locally
ignored.

Change-Id: I6a7dc7fc6a535fe583e9db5878fc496232a69247
Signed-off-by: Soniya Vyas <svyas@redhat.com>
diff --git a/.gitignore b/.gitignore
index 06a2281..9767e52 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,9 @@
+# Don't add patterns to exclude files created by preferred personal tools
+# (editors, IDEs, your operating system itself even). These should instead be
+# maintained outside the repository, for example in a ~/.gitignore file added
+# with:
+#
+# git config --global core.excludesfile '~/.gitignore'
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