Load the custom Ligand Receptor database from the user

Load the custom Ligand Receptor database from the user

LoadCustom(custom_LR_database)

Arguments

custom_LR_database	data.frame. Each row is a ligand-receptor mechanism where the first column corresponds to the source genes that express the ligands subunits (separated by '_') and the second column corresponds to the receptor genes that express the receptor subunits (separated by '_').