Update 3_use_cases.md

Added section for projects built using aligned. So far have only added a quick note about the Mina bridge and a link to the github. Would like to discuss other projects before adding, and also improve the overall formatting of this entire page.

Author: bjdyakov

docs/1_introduction/3_use_cases.md

@@ -13,3 +13,7 @@
 - Encrypted Mempools using SNARKs to show the correctness of the encryption.
 - Protocols against misinformation and fake news: you can generate proofs that an image or audio comes from a given device, and show that a published image is the result of certain transformations performed on the original image.  
 - On-chain gaming.
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+## Projects built using Aligned
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+- The Mina <> Ethereum bridge (in development) uses Aligned's fast mode for ZK proof verification. See the [github repo](https://github.com/lambdaclass/mina_bridge) for more information.