Sourcetree is a simple and powerfull Git GUI.
After working on a feature with separate branch, we may want to integrating the feature to the master branch using rebase instead of merge, so the overall history will look much cleaner and neater at the end.
Step 1: Checking out to feature_a branch, right click the master branch and rebase interactively
Step 2: Select the top most commit, and squash with previous commit
Step 3: Edit commit message, summarize all commits in feature_a
Step 4: Rebase is done and the overall commit history is look much neater now
Use the force push options to push the changes to the remote origin.