Squash migrations

[eugenk]

We have gathered a lot of migrations in the past year. This pull request squashes all migrations into one big schema migration and removes the data migrations since they have been all been applied to ontohub.org.

In my opinion, this is needed because some schema migrations made changes back and forth and this new squashed migration shows the clean state. Also, this speeds up rebuilding the database on our development machines a little bit.

I used the gem squasher to do this. After executing it, I re-added the SQL functions and some data at the bottom of the init_schema migration (copied over from the previous init_schema and added omn to the ontology file extensions).

[SGraef]

👍

[eugenk]

I rebased on staging and there were conflicts:

UD db/migrate/20150217121518_create_loc_ids_for_existing_ontologies.rb
UD db/migrate/20150311125212_make_sentences_to_axioms.rb
UD db/data/20140823134219_set_count_fields_correctly.rb
UD db/data/20141102203932_update_display_text_for_obo_sentences.rb

Those updates only added the original scope on Sentence/sentences calls or removed an unscoped. This is irrelevant for this squashing. However, I want to wait for another sign off because of the conflicts.

[SGraef]

👍