use facade for TenantScope and add TenantColumn method
add possibility to use multiple tenant columns
allTenants must be static
introduce addTenant
add getTenantScope method to model
add static getTenantScope method to model
change variable name "tenants" to "tenantAttribute"
Reformatting and rearranging
Refactor
Fixes #15
Writing TenantScope tests
Refactor observer into scope and test
Started on trait tests
Updated README.md
Add call to HasTenant instead of isset
Merge pull request #17 from arielstt/refactor

Add call to HasTenant instead of isset
Merge pull request #13 from AuraEQ/refactor

Big Ol' Refactor