docs: adds Martha's user stories for lesson 05 (#249)

* feat: add README of user stories for lesson 05

* feat: add acceptance criteria

Author: imo-252

lesson_05/marthao/myfitnesspal-user-stories/README.md

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+### User Stories
+
+1. As a dieter, I want to scan the barcodes of the foods I eat, so that I can automatically get their nutrition facts.
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+2. As a fitness enthusiast, I want to track my macronutrients, so that I can make sure I am meeting my daily intake goals.
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+3. As a fitness enthusiast, I want to find recipes based on a particular diet, so that I can cook foods that align with my fitness goals.
+
+### Acceptance Criteria 
+1A. The barcode scanner should work with the device's native camera.
+
+1B. There should be an API integration with a database of foods and their nutrition facts.
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+1C. The barcode should return the food item that exactly matches the universal product code (UPC).
+
+1D. Upon scanning, the full nutrition facts should be automatically returned and displayed to the user.
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+1E. If an exact match based on the UPC is not found, the closest matching product should be returned. 
+
+2A. All food results should highlight the amount of carbs, protein, and fat in the product.
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+2B. Users should be able to see a pie-chart breakdown of their daily macronutrient intake in their dashboard. 
+
+3A. There should be a database of curated recipes categorized by common diets and lifestyles.
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+3B. The nutrition facts should be pre-determined for each available recipe. 
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+3C. Users should be able to directly log the macronutrients and calories of the recipe to their food diary.
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+