Bugs Fixed with ref to issue #19

[Moinuddin9777]

Please add hacktober tags so that this PR gets accepted. The code needed some refactor which was fixed. Build Passing. No conflicts.

[Moinuddin9777]

@iakash-singh

• State management (Riverpod) has been added
• Delete expenses is implemented, you can swipe an expense to delete it
• Local SQL Database feature added so that expenses get recorded in the DB

[Moinuddin9777]

Please add hacktober tags and merge these PRs so that I can work on others and push them