refactor: Add Database.database_exists().
refactor: Add Database.database_exists().

shubhamdhama/zulip,brainwane/zulip,rht/zulip,showell/zulip,shubhamdhama/zulip,rht/zulip,andersk/zulip,timabbott/zulip,timabbott/zulip,zulip/zulip,shubhamdhama/zulip,kou/zulip,timabbott/zulip,kou/zulip,synicalsyntax/zulip,punchagan/zulip,brainwane/zulip,eeshangarg/zulip,shubhamdhama/zulip,zulip/zulip,andersk/zulip,rht/zulip,punchagan/zulip,punchagan/zulip,synicalsyntax/zulip,rht/zulip,showell/zulip,kou/zulip,hackerkid/zulip,brainwane/zulip,synicalsyntax/zulip,hackerkid/zulip,eeshangarg/zulip,andersk/zulip,zulip/zulip,andersk/zulip,andersk/zulip,showell/zulip,hackerkid/zulip,timabbott/zulip,timabbott/zulip,eeshangarg/zulip,eeshangarg/zulip,eeshangarg/zulip,synicalsyntax/zulip,brainwane/zulip,brainwane/zulip,timabbott/zulip,hackerkid/zulip,synicalsyntax/zulip,punchagan/zulip,brainwane/zulip,kou/zulip,hackerkid/zulip,showell/zulip,rht/zulip,shubhamdhama/zulip,zulip/zulip,kou/zulip,hackerkid/zulip,timabbott/zulip,kou/zulip,eeshangarg/zulip,punchagan/zulip,shubhamdhama/zulip,shubhamdhama/zulip,showell/zulip,rht/zulip,zulip/zulip,showell/zulip,hackerkid/zulip,brainwane/zulip,punchagan/zulip,rht/zulip,zulip/zulip,andersk/zulip,showell/zulip,punchagan/zulip,andersk/zulip,zulip/zulip,synicalsyntax/zulip,kou/zulip,eeshangarg/zulip,synicalsyntax/zulip