Fix spelling errors in documentation (#420)

* Update README.md

* Update README.md

common/helpers/README.md

@@ -1,3 +1,3 @@
 # Utils
 In the `utils` package, we have all the functions that could not fit in a specific package.  
-We are storing them the Environment variable seteup, the constant we may need to use accross the program, some very specific utilities, etc.
+We are storing them the Environment variable setup, the constant we may need to use across the program, some very specific utilities, etc.

internal/models/README.md

@@ -1,4 +1,4 @@
 # Models
 The `models` package is kind of the same as the `types` folder in Typescript. It's a registry of all the types we may need accross our program, in a separate package so we could use them and call them no matter where we are.   
 No logic, or the smallest logic should be implemented in here.   
-It's moslty a `give me the struct please` package.
+It's mostly a `give me the struct please` package.