Git_Basics.rst: Add 'Common Git Issues' section

This section will help newcomers sort out basic git issues.

Closes: coala#3140

docs/Developers/Git_Basics.rst

@@ -260,7 +260,7 @@ coala:master`` (or whichever repo you are contributing to), then you
 haven't correctly rebased yet. Otherwise, you're good to go!
 
 Squashing your commits
--------------------------
+----------------------
 
 It's possible that you have more than one commit and you want them to be
 squashed into a single commit. You can take your series of commits and squash
@@ -283,6 +283,58 @@ another editor will be fired up with all the messages of commits which you want
 to squash. Clean up all the messages and add a new message to be
 displayed for the single commit.
 
+Common Git Issues
+-----------------
+
+Sometimes, you use git add-A and add files you didn't want to your push (often
+after rebasing) and push it to the remote. Here ,is a short outline of, how can
+you remove (or revert changes in) particular files from your commit even after
+pushing to remote.
+
+In your local repo, to revert the file to the state before the previous commit
+run the following:
+::
+
+    $ git checkout HEAD^ /path/to/file
+
+Now , after reverting the file(s) update your last commit, by running :
+::
+
+    $ git commit -a --amend
+
+To apply these changes to the remote you need to force update the branch :
+::
+
+    $ git push -f myfork
+
+.. note::
+
+    The procedure outlined above helps roll back changes by one commit only.
+    'myfork' mentioned above is your forked repository, where you push your
+    commits.
+
+The ``git checkout <revision sha> path/to/file`` command offers you more
+flexibility in reverting the changes in a file, done even from earlier than the
+last commit. By replacing the ``HEAD^`` by the revision number of the particular
+HEAD commit, you can refer to the required revision of the file.
+
+Might sound a little intimidating, but don't worry, an example has been
+provided for you.
+First you can check the commit's revision number, where the file was revised by
+running the following command:
+::
+
+    $ git log /path/to/file
+
+The revision number might look like ``3cdc61015724f9965575ba954c8cd4232c8b42e4``
+Now, to revert the file to that revision, run the command:
+::
+
+    $ git checkout 3cdc61015724f9965575ba954c8cd4232c8b42e4 /path/to/file.txt
+
+Now, after the file gets reverted back to the required revision, commit the
+changes and (force)push to the remote.
+
 Useful Git commands
 -------------------