removed EventSearch class
added serializer service which should serialize objects for indexing
added SearchIndex model to store schema for search index
added index_settings to ApplicationSearch and use tire.import when recreating index
added tests for serializer service
removed models for indexes
removed tests for serializer factory
added additional_index_mappings to index_mappings
fixed gathering class name for additional mappings
refactored IssueSearch
changed IssueSerializer
removed unused files
add additional_index_properties when building serializer class
allow to recreate index asynchronously