New article: Software Design Pattern

# Title: Software Design Pattern

- [ ] What is this about: “What is this practice about”? Which existing (or new) problems does this practice solve?
In software engineering, a software design pattern is a general, reusable solution to a commonly occurring problem within a given context in software design.

- [ ] Read more here: The starting point for your research (You can use different sources if you have better ones)
https://en.wikipedia.org/wiki/Software_design_pattern

- [ ] Pick the corresponding labels:
- Stage:research
- Stage:building_team
- **Stage:development**
- Stage:launch
- Stage:maintenance
- Stage:phase_out

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