doc: Move rationale to main docs

README.md

@@ -74,70 +74,6 @@ $mapper->map($book, $bookDto);
 
 [rekalogika.dev/mapper](https://rekalogika.dev/mapper/)
 
-## Rationale, or Why Create Another Mapper?
-
-We developed a project that during its planning phase we determined that it
-would be beneficial to integrate an automapper into the architecture. We looked
-around and found some potential automappers, and decided to go ahead with the
-planned architecture.
-
-We first tried
-[AutoMapper-Plus](https://github.com/mark-gerarts/automapper-plus) and
-immediately ran into the issue that it reads and writes directly to properties,
-including private properties, which is unacceptable to our purposes. For
-example, we store monetary values as integers in the object, and convert them
-from and to `Money` objects in the getter and setter. Using this mapper, it
-would get the raw integers, not the `Money` objects. We also feel it violates
-the principles of encapsulation. However, this was not a blocker as it supports
-a custom property accessor, and it was possible to resolve this issue by
-creating an adapter that uses Symfony PropertyAccess component.
-
-With AutoMapper-Plus, users are expected to create a mapping configuration for
-each mapping pair. It has an automatic creation of mappings for simple mapping.
-All of our entities and DTOs are typed, but we need to create a mapping for
-every non-trivial pair, despite the type information is already there in the
-involved classes. Custom mapper is available, but it does not let us access the
-main mapper. If a mapping pair uses a custom mapper, we are responsible for
-mapping everything, including nested objects, because the option to delegate to
-the main mapper is not available. There was another case that was simply not
-possible to accomplish, I don't remember what it was, but it forced us to switch
-to another mapper overnight.
-
-Our next mapper was [Jolicode
-Automapper](https://github.com/jolicode/automapper), formerly known as [Jane
-Automapper](https://github.com/janephp/automapper). It behaved as expected,
-there were no big surprises, and there was very little to complain about its
-behavior. It is very fast as it compiles its mapping code to PHP files. The
-problem was error handling. When an error occurred in the compiled mappers, it
-was usually a `TypeError`. It was difficult to debug, and even more difficult to
-resolve the problem. Addressing the problem requires the skill of working with
-AST. We found that the problems were usually deployment errors (usually
-forgetting to clear the cache), some edge cases (easy to work around), or bugs
-in the mapper. It was rare to get an error, but when it happened, it was
-difficult and time-consuming to resolve. We did contribute some fixes back to
-the project.
-
-The second problem was that the mapper was difficult to extend. Adding a new
-transformer requires the knowledge of working with AST, and there was no option
-to do a mapping using plain old PHP code that you write yourself. We hit a brick
-wall when a new requirement surfaced that requires the mapper to target an
-abstract class, a feature that was not supported by the mapper. We figured it
-would be easier for us to spend a week creating our own mapper from scratch
-using our experiences with the other mappers, and here we are.
-
-Other mappers that were considered:
-
-[MicroMapper](https://github.com/SymfonyCasts/micro-mapper/) is a mapper that
-requires you to write the mapping code yourself. It is all manual work, but
-still working within the mapping framework, and should be suitable for our
-purpose, as long as we are willing to write the mapping code ourselves. The
-mapping code also supports delegating to the main mapper, unlike
-AutoMapper-Plus. However, at this point, we were way past of contemplating
-whether to do it manually, so we did not consider it further.
-
-[Pull request for a future Symfony Mapper](https://github.com/symfony/symfony/pull/51741).
-In the form that I saw it, it was too simplistic, and does not provide any
-extension points. I (@priyadi) did provide some feedback in the pull request.
 ## License
 
 MIT